Depending on the tarp sizes, and other stuff like strategically taped cardboard, you can recover about 85-90% of it. The problem I ran into yesterday was that the really small dust I was recovering tended to clog the intake side of the hopper. There wasnt enough air space between the grains of aggregate to allow it to suck through. I kept thinking it was a clog from rust scale so I spent too much time sifting sand looking for bits of trash. There wasnt any. Once it starts getting really pulverized this bucket blaster refuses to work. I will buy a bag or 2 more for when I have to do body panels. I wont be blasting the flat expanses, just the jamb areas to clean them out.