For the glass, as well as any ALL metal parts, you could try acetone. Your local hardware store should have it. It WILL dissolve the gunk, but don't get it on anything plastic; it will likely melt it if it's not polyethylene or Teflon. I've been using it on other glass, metal and ceramic smoking appliances for years. It evaporates quickly and completely and is miscible with water so it washes off.