The best non-flammable product to use to get rid of the glue residue is named Goo-Gone. I have purchased this stuff at hardware stores, most recently at a Sears hardware, and I have also seen it at one of the area hobby shops. Best stuff in the world for removing the junk left over after peeling price stickers off of propellers. I once bought a ducted fan jet kit at a swap meet where the owner had, some ten years prior, used everyday masking tape to mark the cut lines for gear doors and hatches on the fiberglass fuselage. Well that tape had long since petrified on the fiberglass yet the Goo Gone took it right off. Great stuff.