Years back there used to be a brand called Captain Lee's I'd buy at the swap meets. Had lots of Methylene Chloride in it. Nasty stuff for sure but it worked, til the spray bottles they gave you to apply it froze up from the rapid evaporation of the methylene chloride. Chances are the EPA stepped in and severely reduced the usage of that chemical. Along with sanding you might try enhancing your stripper by laying newspaper or plastic over the top of the parts after laying down the stripper, to help keep it from evaporating.