Here is a goal: Remove old bumper stickers from automobiles without using solvents.

How would you accomplish this goal?
Old bumper stickers and other types of stickers can be removed from automobiles easily with hot air. Use a hair dryer to heat up the sticker, which will also heat the adhesive on it. Once warmed, the bumper sticker should be peeled slowly away from the automobile while still applying hot air from the hair dryer. This will remove the bumber sticker without use of any solvents.