Use Cotton Drop Cloths Rather Than Plastic
But even with canvas or rosin-paper drop cloths, large spills still need to get wiped up right away or they'll seep through. Clean spills with paper towels or cloth rags. Likewise, if you splatter paint on any other surface, wipe it up immediately.
Paint Tray Liner
Glad Press'n Seal plastic wrap is meant to seal food containers. But it also makes a great paint tray liner. When you're done painting, just peel the sticky plastic off the tray and throw it away— no paint-caked tray to clean up.