I came up with a method to remove vinyl stickers that isn't too hard. At first, I tried heat gun plus peeling, but it didn't work well at all. The vinyl sticker material is too insubstantial and kept breaking before I could get a peel going. When I did get some areas to peel, it left behind so much glue that getting it off was harder than getting the whole thing off via the method below:
1) Heat: heat the entire surface of the sticker with the heat gun, little by little, until little blisters appear over the entire surface. This prepares the sticker for further breakdown via chemicals.
2) Goof Off: spray pro-strength Goof Off on the stickers until they disintegrate. I started when it was still hot and the first couple shots instantly evaporated. I doubt this is necessary. At first I sprayed and rubbed concurrently, but later realized that a couple of rounds of spraying with wait times removed most of the need for force and friction. The Goof Off destroys the sticker and it eventually gets all crackled and raised like paint
subjected to paint
stripper. At this point it practically wipes right off with one swipe of a plastic scraper.
3) Wipe off remaining mess with acetone.