how do i get old decal letters off my alum boat and not damage paint?

Heat them up with a hair dryer or heat gun to soften the glue then try to peel them off carefully...

Try with a small piece of decal using a hair dryer and a razor blade to peel it off. Heat usually softens up the glue and makes it pretty easy to peel off most decals. I've tried the chemical solvents, and they're messy and ineffective.

use heat like others have stated, but to remove the glue residue use some old style lighter fluid(naptha) put some on a cloth and rub in. almost always never hurts paint(I would try on a small out of way spot if your worried). use more fluid as necessary. this stuff works great on most surfaces and has been used for decades to remove shoe scuffs from floors and other marks in the home. I have used it for years in my shop on boats, motors, cars,snomobiles etc. works great.

ps has other uses to so is cost effective

Go to autozone or someplace similar, and ask if they have any decal remover? Autozone used to carry some kinda solvent kinda like turpentine or similar thinner that did just that, remove decals etc off boats,airplanes and autos. I forgot what it's excactly called, but someone there might be able to help you. I think its glue begone or something.

heat it up using a blow dryer, use credit cards or anything plastic resymboling a credit card. keep sliding the card under the decal until you've removed it....after its removed, get goo gone and spray it on it. let it sit for a couple minutes and use the card to rub of what extra residue its left behind. continue doing this until its gone. then use either quick wax or hard wax and wax the area thats been uncovered. done.

Wal- mart has this stuff called De Solv- it it removes wax gooey messes and decals . I also use it on clothes if i get grease on them it really works .

Try WD-40

blow dryer. Heat them up a little they will peel right off

try a hot air gun on low power

use a sharp blade and http://www.googone.com/ to get rid of the adhesive.