How to identify lead paint?
Rough up the paint with sandpaper, and then use Aircraft Remover to get the paint off, if you try to sand it, you'll go crazy. DO NOT use aircraft remover inside, and wear a filter mask, it will make you sick if you don't. It will rip the paint right off.

http://www.rustoleum.com/product-catalog/consumer-brands/auto/paint-chemicals/aircraft-remover