How to remove strong adhesive from back of iPhone?

If you want to remove the sticky adhesive, don't use acetone (nail polish remover). This might damage the finish. Instead what I found useful is lens cleaner, a fingernail, a lens cleaning cloth and a lot of patience, if your method leaves residue. I could say to use another product found at hardware stores, but that would more than likely damage the finish. I did that method to remove stickers off an old laptop I gave to my mom. It took a lot of time and patience, but I got the stickers off completely. After the lens cleaning solution sets then use your fingernail to scratch at the adhesive. When it's all off, then you can buff it and it'll look like it wasn't there.

One trick that I've seen used on other things is to use something like a fishing line stretched tight and moved back and forth to saw through the adhesive between the object and the phone.