Hey guys. I recently purchased a home built in 1960. There are a couple areas on the ceiling that is crumbling/falling. To be honest, I'm not sure if I have a drywall ceiling or a plaster ceiling. How can I tell? Under one of the areas, I see a flat, shiny surface(if that helps). I'm just not sure if the fallen pieces are actually joint compound (from a drywall ceiling) or plaster. The pieces are thin, perhaps 1/8 in.