best way to remove vinyl top glue?

Have you tried rubbing alcohol? I'm not sure if it will work, but worth a try.

Or try heating it up with a hair drier/hot air gun and soften the glue and scrape it off with a plastic paint scraper. Then a solvent for the left over residue.

The three basic solvents are water, alcohol, and mineral spirits. One of them should work. You may have to let them soak for a bit...