While I have never repainted fiberglass on any of my models, I have done a lot of fiberglass work on my full size boat. Chemicals around the fiberglass are a definate no-no. The chemicals can seep into the resin layer (especially if there are any cracks in it) and weaken the resin which can lead to failure later on down the road. I know it's a lot of work, but elbow grease is the only real way to get it off. A great help in this area is the Black & Decker Mouse sander. It's small enough to fit in one hand and does a great job of doing the elbow grease work for you. You can get one at Wal-mart, and I think they are less than $50.