Duct tape — or Gorilla Tape — is great for lots of things, but it’s not known for coming off cleanly, particularly if it’s been hot.
I used to use acetone, then I switched to Goo Gone. About five years ago, a contractor friend of ours said to use WD-40 — he swore it was better and much cheaper.
Since then, that’s what we’ve used. And he was right — it easily removes tape residue that took forever with Goo Gone.
Use a rag with a bit of texture to it — for example, terry cloth as opposed to an old t-shirt — and soak a small area of it with WD-40, then scrub at the residue. If there is a lot of tape gunk to get off and nothing nearby that the WD-40 would hurt if it ran or dripped, you can spray the residue and let it sit for just a minute before scrubbing.
Obviously, don’t do this on anything that the oil in WD-40 would harm! After removing the residue, I usually use a bit of soap and warm water to wash the area so it’s not slick from the WD-40. It’s really important to wash the WD-40 off if you’ve gotten it anywhere that people will walk as it is extremely slippery.
NOTE: Some people prefer to use Gaffer’s Tape to duct tape because it leaves far less residue. That’s true — it’s wonderful tape — but it’s also much more expensive than duct tape or even Gorilla Tape. We prefer to save it for times when we really need the “leave no residue” feature (see Gaffer’s Tape on Amazon if you’re not familiar with it — we weren’t until a reader recommended it).