If the surface is glasslike, I'd try and scrape it off. Get one of those flat scraper razors and go slow. If the surface is glassy enough, maybe you'll get a lot of it that way. At least get the top layer off so less chemicals will be needed and you can focus on what's left with a toothpick to keep the surrounding area safer from the chemicals.
Worst case, sand it down and refinish it. SW has PB paint colors.