i have a few 30 and 50 gallon plastic drums that came from a carwash. i was thinking about making a couple electric spray rigs out of them. i would probably just use them for selective herbicides. is there anything wrong with useing those drums for this reason. i have one of the 30 gallon drums that i fill with h20 now that i have put a hose bib in the bottom to fill my back packs with.