[DinDinA-2]

Try an orange based gell paint stripper. I once had a rem 700 w/ large scope covered with white water proof first aid tape. It was on for years as camo. When I decided to sell it, thought it would be easy to clean up. Wrong. The tape came off but the adhesive stayed behind, like some new space age coating. Nothing would touch it, not even the usuals...including Goo Gone (a favorite) or Goof Off. The Orange Gell Paint Stripper did a fantastic job on the synthetic stock, rifle and stock. It looked like new when done.

Found it: "Citristrip" Safer paint & varnish Stripping Gel.