Mine peeled right off. It's not enough stick to damage the paint (just don't use a screwdriver or putty knife

). It left some very small sticky spots and for that I did the following...
If you leave some sticky stuff on the tank, use the sticky part of the sticker and rapidy press/rub it on and roll it off of the sticky parts, that usually does the trick.
You can also just use friction by rubbing a finger or thumb (use some good pressure) and rub the sticky part (until you almost burn your finger

) then it rolls off in a ball.