Chipp

Have you tried squeezing an orange rind on it ? Pure orange oil disolves many of the adhesives out there.As the story goes a 3M engineer was developing a cleaner and while peeling an orange some of the oil got on the goo and Viola. Their industrial Citrus cleaner is unbeatable. E.B. Bradley sells it for $15 a can but it lasts a long long time. Hope this helps.