How To Store Paint
Before you put your paint away for storage, don't forget to mark each paint can with a permanent marker - write down the colo rname/code and room/surface it was used for.
Also, make sure there is a paint dab on each can to show you what color is inside for easy identification.
First of all, paints must be stored in a dry place, off the ground or concrete floors - to keep the cans from rusting.
It's better to store paint in a cool area - but don't allow it to freeze, or it will separate and become unusable.Also, keep it away from direct sunlight or other heat sources that will speed up paint's deterioration. The above requirements usually mean that an unheated garage, basement, attic or shed is out, but a utility closet or a laundry room should be fine.
All paint cans are bulky and take up a lot of space, so consider storing paint leftovers in smaller containers - canning jars work fine for that. Besides, paint keeps better in full containers, where it has less contact with air.
Before closing a paint can or a jar, be sure to wipe clean all the paint residue from the groove/rim - that will make it easier foryou to open it when you need to, and will not allow air in by making the lid fit tighter
To create an even tighter air seal and prevent metal-to-metal corrosion, you can take a plastic bag and cut out acircle larger than the opening of a paint can, and use it as a gasket under thelid.
Don't hammer the lid directly when trying to close the can -this may distort the lid and disrupt the air seal. Instead, use a rubber mallet, or place a block of wood on top of the lid and hammer the wood block toset the lid firmly into place.
When it's time to open the can and use the paint again,always check for paint "skin" that can form on the top, especially if thepaint has been stored for too long or hasn't been sealed properly.Carefully remove it with a stick or spoon before mixing the paint, oryou'll end up with paint full of "skin" pieces and debris.
Original article from the excellent website - housepaintingtutorials.com