
Step one in our boat interior renovation was to clean and refinish all the interior teak. There were several problems that needed to be addressed: it was very dark, there were light places where previous owners had pictures, there were screw holes, and there was what can only be called a gunky buildup where hands had rubbed daily. And on what should be a gorgeous showpiece counter, there were black rings from where — apparently — a can of used oil had been set down.
In this article, I’ll talk about choosing a teak cleaning and finish system. In subsequent weeks, I show the step by step process I used to clean the teak, finish it and fill in all the screw holes.
Here’s what I was starting with.


The rail next to the steps to go down into each hull was literally black with oil and gunk from hands grabbing it many times a day. The teak in many areas of the galley was also black.
My goal was to clean the teak so that the black was gone and it was a uniform color — hopefully a nice light teak color, not the dark almost mahogany color that it had become. Then I wanted some sort of a finish on the teak to protect it and keep it looking nice.
To be honest, I didn’t know exactly what I wanted. I did know that I didn’t really want varnish, both as it tends to darken teak and I wanted something that was easier to apply. I also didn’t want something that was prone to cracking and peeling.
Another option was Cetol, which gives a look similar to varnish. It just wasn’t the look I wanted and it can also bubble, crack and peel.
I was looking for both a cleaner and a finish, and I knew that usually, it was best to use products designed to work together.
I knew that previous owners had used teak oil on it — I’d found numerous partial bottles of different brands when we’d first moved aboard. But my basic research said that most teak oils simply fed mold and the blackening.
I’d used Semco on the teak on the exterior teak on our previous boat, Que Tal, and that was a possibility — Semco is very much like Thompson’s WaterSeal, but for teak on boats. Semco is extremely easy to apply, but I wasn’t sure it really was the look I wanted inside the boat.
And then there was the whole cleaning process. I knew this was going to be a big project, and wanted something that would work with a minimum of effort. But I also wanted something environmentally friendly. And since I was working inside the boat, I didn’t want anything that required massive hosing down or caustic chemical brews. I didn’t want anything that would hurt the gelcoat abutting the teak. Most two-part solutions were quickly ruled out as being too harsh, not environmentally friendly, hard to use and potentially damaging to the gelcoat.
I began researching and after a bunch of reading, discovered the Teak Guard family of products. The Super Cleaner got high marks for effectiveness and ease of use, as well as the fact that it was non-toxic and wouldn’t harm gelcoat. Further, it would actually kill any mold or mildew spores present so that the wood wouldn’t start blackening under my new finish. (I learned that solutions using bleach or TSP also won’t kill the mold and mildew.) I was somewhat skeptical of the claim that it took only 1/10 the labor of the company’s previous cleaner formulation but I thought that it looked like the best option I’d found.
The Teak Guard Finish also looked like a winner. First, it would not feed mold and mildew. Second, it breathes so that any moisture in the wood can simply escape rather than causing the finish to crack and peel — the problems I’d had with varnish and Cetol. I absolutely did not want something that I would have to repeatedly clean or sand in the future both from a work standpoint but more importantly because most of our teak is thin veneer and simply can’t be sanded many times before it will be gone.
Much of the TeakGuard literature talks about using it for exterior applications (including boat decks), and so I called the company to get a little more information. Yes, it can be used inside. For outside use, they recommend a maintenance coat every year but as the interior gets far less UV, it would probably only be needed every two to three years when the finish started showing a haze. But there is no sanding or deep cleaning needed before the maintenance coats — just washing with soap and water.
The fact that Teak Guard produces a non-slippery finish was a bonus. I’d long wanted to redo the floors with something other than the varnish/urethane that was presently on them and eliminate the rugs — I wanted to see the beautiful teak and holly floors.
All in all, this sounded like the type of cleaner and finish that I wanted! There’s also the fact that I liked the look of Teak Guard Finish in their pictures.
I ordered their “Starter Kit” and began by cleaning and finishing one sliding door handle to see how it worked and if we liked the look. Yes, we did! I continued with the project, cleaning a small area each day, letting it dry overnight and then putting several coats of finish on over the next few days. The company recommends waiting no more than a day between cleaning and finishing so that the wood’s natural oils won’t rise to the surface and allow mold to begin forming again.
It is slightly cheaper to buy a small bottle of the Super Cleaner and one of the Finish than to buy the Starter Kit that includes various cleaning tools. I used their tools at first, and they’d be good for teak that is not badly stained. I ended up using a somewhat different technique for dealing with my really awful teak from the instructions they gave — I’ll detail it and the tools I used in the next article in this series.
For any substantial amount of teak work to be done, their half gallon bottles are a far better deal. As my teak was in such awful condition, I found that I needed about twice as much Super Cleaner than what their usage guidelines suggested. I put 4 coats of Finish on most vertical surfaces, 6 to 8 on horizontal surfaces and 10 to 12 on high traffic areas such as handholds and handles.
As I write this, the company’s website is very temporarily down (it should be up by the end of the week and as soon as it is, I’ll post a link) but you can order by calling them at 800-488-TEAK (8325).

For now, I’ll show that counter as it was partially cleaned and then as it was when completely finished (the “before” picture is at the top of this article):


And here is the wall behind the settee, half “before” and half “after” the first pass of cleaning. I did still do a little more cleaning on the left-hand side so that it was an even color:
Note: I chose TeakGuard products through my own research and initially bought the products at retail. Highly impressed with how well they worked, I contacted the company with before/after photos to show just how well it had worked. One thing led to another and they gave me additional amounts of their product to complete the job.
Some links in this article (including all Amazon links) are affiliate links, meaning that we earn from qualifying purchases.
Kay Schardein says
Carolyn,
We are winding down our cruising life, selling our beautiful Westsail 42 but I am thrilled to find WWS even at this late hour, and a reminder of your site which I used to follow. Cannot wait to read your varnish solution series – just in time and what I need to restore our interior’s teak to its former beauty. Carry on!
Kay Schardein
S/V Chamisa
San Carlos, Sonora, Mexico
Greg Cantori says
As always great background and actual trials! Our 1984 Freedom was showing it’s interior age as well. Faced with the daunting work of striping and refinishing I experimented with a few stain only products which worked but were too dull. Then tried Restore a Finish. Like magic it’s a stain and finish in one wipe on and off. https://www.howardproducts.com/product/restor-a-finish/
Gail Vernon says
Hi Carolyn,
I see that you’ve used Semco in the past and are now using Teak Guard in your interior. Any thoughts on using Semco vs Teak Guard on the boat’s exterior? Thanks. (BTW, love your site, so useful!)
Gail
S/V Fancy Free
Carolyn Shearlock says
It depends on the look you want. Semco looks like bare teak, but protected. TeakGuard looks more like a satin finish. TeakGuard needs one maintenance coat a year; Semco is going to need one every six months or so (depends on UV and rain for both). TeakGuard is a bit more slippery as far as using it on a deck would go, but still not truly “slippery” as long as you don’t sand the grain down. Teak Guard will take more coats for the initial application. Since I haven’t actually used TeakGuard on the exterior, I can’t say anything for certain . . . But if I had a boat such as our previous one with lots of exterior teak, I’d definitely try the TeakGuard as I really like the look of it and it was really designed for outdoor applications so it should be fine. And the breathable aspect means that it’s not going to crack and peel like varnish and Cetol.
Stacey says
I’ve heard some people clean the teak, then apply varathane/varnish coats, and don’t have to touch it for years afterward. Any reason why you didn’t go this route, and save yourself repeat coats of Teak Guard in the future?
Carolyn Shearlock says
When varnish starts to crack and peel, you have to sand it down to bare wood. Over time, you end up with less wood and can sand right through veneer. Also, varnish is MUCH trickier to apply well. TeakGuard is easy — see my info on applying it: Boat Renovation: Applying Teak Guard.
And if water sits on varnish for any length of time, the varnish will bubble. If it’s not repaired immediately, the wood will mold underneath. TeakGuard won’t bubble and won’t mold.
SUSAN JONES says
I am new to the world of teak care. Having acquired a Bristol 47 this past summer, my husband & I are considering the products to use. I am very impressed with the results and care required with the Teak Guard. My question is….not knowing what products were previously used on our boat….do I need to strip my teak totally down to raw teak? Will the super cleaner do this? or do I need to use a harsh chemical to remove varnish? The outside teak finish is in pretty good condition – renewed by previous owner prior to putting the boat on the market.. I plan to do some test areas inside to start and gain some experience with the Teak Guard. Your thoughts would be greatly appreciated.
Lance Olshovsky says
All I can say is WOW and THANK YOU!!! I was about to attempt what I thought was to be a daunting task of teak cleaning and finishing. (Hearken back to the days of Formby’s Furniture Refinisher when as a young kid, I tried and re-finished numerous antiques we had at our family farm. BOY! That was a not so fun task). So, after I received my kits last week, and almost memorizing your procedure here, Carolyn, I am beyond elated at how simple this is to what I had conjured up in my mind. THANK YOU THANK YOU THANK YOU!!!!!
Pam Kemps says
I called the manufacture and they suggested I use a stripper prior to the work (I don’t know what is on my boat now), they suggested Blue Bear soy gel stripper – I can’t find any locally near me (Vancouver BC). Can anyone suggest an alternate? After the stripper they said to then use a degreaser too.
Carolyn Shearlock says
Can you find another soy stripper??
ART WATSON says
Hi Carolyn,
I am thinking that my beautiful — but forty-year old — interior teak has gotten too dark over the ages. I would like a lighter overall finish, and your praise of Teak Guard makes it seem very attaractive. But there is a LOT of teak down there! A previous questioner asked: “do I need to strip my teak totally down to raw teak (presumably, before applying any Teak Guard product)?”
That’s the question I have, Will I have to sand or strip all my teak right down to the bare wood before applying Teak Guard? And, having done so, will I still need to use the cleaner first? And can I use t he cleaner on the bare wood without damaging it?
Thanks!
Carolyn Shearlock says
Yes, you have to go down to bare wood before using Teak Guard, and you MUST use the teak cleaner on it after getting to bare wood (or with new teak). The cleaner is designed to be used on bare wood, so no, it won’t damage it.
Jeff says
I have a simple teak table I just bought for my cockpit. The manufacturer says use a wax, and I’ve obviously heard about teak oil as well. People have said they really like semco, as you mentioned here. What would be your recommendation on a table? I’m in New Jersey and boat is only in 6 months a year.
Carolyn Shearlock says
Any of those can work but I’m not a fan of teak oil as it attracts dirt and mildew. My favorite, as I said in the article, is Teak Guard. It’s great.
Stu Pippin says
Cannot find website and ph # you listed does not work. I can find product but no information.
Carolyn Shearlock says
The website is here: https://www.allguardproducts.com/ Their phone number is 800-448-8325
brian bouch says
Previously you recommended Formby’s, now Teak Guard. So, who gts the nod?
thanks
Carolyn Shearlock says
I used Semco on the exterior teak on our previous boat and think it’s great for that — it’s basically like Thompson’s WaterSeal, but for teak. I wanted a bit more glossy look for our interior teak and chose TeakGuard, which I also love. Both are MUCH easier to apply than varnish and don’t trap water underneath, leading to mold and flaking.
I’ve never used Formby’s. The interior teak on this boat had years of built-up teak oil (which Formby’s is) and was a black, gooey mess as it had never been cleaned between coats. I personally don’t like teak oil in general, as it tends to promote mold.
Linda says
We have just sold our monohull in Indiantown FL last week and are looking to buy a Gemini 105, after visiting Ken/Kelly on theirs. While traveling south for the sale we looked at 4 of them and have noticed a lot of darkening, staining, (rings and running). The broker said to use Oxalic Acid, any thoughts on that? I had also read about Borax soap and water?? Also mold in the compartments 😳 the broker said to paint the inside of the cabinets with Kiltz as it inhibits mold growth? Any thoughts on all this clean up, thanks!!
Carolyn Shearlock says
YAY! I think you’ll love the Gemini!
Yes, oxalic acid works well. For minor stains, you can use toilet bowl cleaner. FSR (Fiberglass Stain Remover) also works well.
Yes, Kilz will inhibit mold — we use it as primer everywhere in the boat and also use a mold inhibitor that’s a paint additive (pretty much any paint store in Florida will have their own brand of mold inhibitor additive).
Cheryl Shedd says
Thanks so much for this helpful review and product suggestions. My concerns echoed yours. I’m ready and eager now to go forward cleaning and refinishing the interior teak of our 40 y/o boat which has probably never been done previously.
One question with regard for the manufacturer’s recommendation to thoroughly rinse the teak cleaner from the wood before applying the finish: People say, “it’s a boat, it can get wet below decks.” But it will be a significant amount of water for these large expanses of teak. When rinsing the vertical areas above storage lockers, cubbies, and over bunks, how did you manage the run-off of the rinse water?
Carolyn Shearlock says
I used several heavy-duty trash bags as “tarps” that I taped into position with blue tape.