Save yourself a trip to the store. Next time you need to clean, try one of these 31 secret cleaners that you already have at home.
Cut the crust off a piece of white bread, squish the bread into a doughy ball and use it to gently dab the surface of paintings (but not valuable or antique works). Once the ball is covered with dirt and grime, start again with a new slice. Use a pastry brush (or another soft-bristled brush) to clear off any crumbs.