I usually start with water, then soap and water, thinner, laquerr,acetone, xylene, carburetor cleaner, brake cleaner, and then buy new parts. In that order for safety.
Xylene is the same thing as goof off except goof off has alcohol added for faster evaporation.
Xylene seems to work great on a huge variety of products.
Sounds like you need new parts.
A pillars are usually the first to rot.
Good thing their cheap and readily available.
There is a pair of A pillar trims for sale here in the parts for sale section.