used a heat gun to kick it off. Once I used a "hot batch" with a bit more catalyst to start the drying process again and once nothing seemed to work and after a year it's still sticky. I guess if one of the above didn't work I would scrape as much off as I could and start over in a warm environment. With polyester resin either the heat gun or the hot batch is likely to work. Most of my trouble was related to epoxy resin. I don't think that even with a great deal of scraping you will be able to get it all off but you might be able to get enough off so that the re-coating heats whats left enough that it wouldn't make that much difference. Boy, I hate doing things twice. Good luck