I have used '3M's Adhesive Remover' with great results. This is found in a 1 quart can. Once you wipe it on,let it soak, and then finish it off with a razor blade.
Carl Rychlik N.E. GS/GN Club
GSCA #2090 BCA #23261 BPG #1064
1970 Gran Sport Stage 1 Coupe-BCA Senior Gold Award-2005 ,BCA Senior Gold Preservation Award 2011, GS Nationals/Larry Miller Best Of Show Award 2011, & HEMMINGS MUSCLE MACHINE OF THE YEAR-2006, AACA Junior and Senior 2010,GSCA 10th year Gold Concours 2015
1987 Grand National (original owner)
2006 Chevrolet Silverado 2500HD Ex.Cab w/Duramax