Actually, that is the way to do it too. Durabound - we use it all the time, so it neveer sits around. Spray mix (ceilings).... we bag up in a trashbag....to keep the moist air away from it.I had a leftover half-bag of tile mortar. I rolled the paper bag shut, put it in a plastic trash bag and used it again 2 years later. Another year and the tile is still stickin'. It's in my house so I should know.