How to Store Paint. Ever wonder what to do with the paint leftover from your painting projects? You don't want to throw it away-its bad for the environment-and you just might need to do a little touch up sometime down the road. However, if you do store it, a year from now when you open the can, the paint is probably going to be all lumpy and goopy or the inside of the can will have rust on it-and after the hassle of storing it-it won't be useable anyway. Well here's some tips on how you can safely store your leftover paint.
Start by wiping away any paint residue left in the rim/lip of the paint can. The secret to keeping paint usable is to keep air out of the can
Cut some plastic food wrap or a plastic grocery bag into a circle a couple of inches larger than the size of your paint can.
Place this plastic on top of the paint can before replacing the lid. The plastic acts as an air seal or gasket, keeping air away from the paint and preventing the paint from drying out.
Add some extra protection by blowing into the leftover paint can before putting the plastic gasket in place. Blowing into the can displaces some of the air in the can with carbon dioxide in your breath.
Reseal paint cans using a rubber mallet (not a hammer). If you don't have a rubber mallet, use your hammer to tap on a block of wood to fasten the lid. (This prevents the lip of the can from being damaged by the hammer.)
Store your paint in a cool, dry place, out of direct sunlight and away from heat sources like furnaces or hot water tanks.
Ensure you don't allow your paint to freeze. While some paint can be used after freezing, a lot can't.