Anyone who has stored a bit of "touch-up" paint in an unheated garage or basement over a cold winter has likely wondered whether it is still OK to use when it thaws out. Unfortunately, if the paint is water-based -- as all latex paints, regardless of sheen, are -- the answer is usually, but not always, no.
Stirring the Pot
Allow the paint to thaw out gradually at room temperature. Never try to thaw it quickly using heat, or you may further damage the paint emulsion.
Stir the paint gently in the can with a stir stick or rotary stirrer.
Remove the stirrer and check the result. Good, usable paint has a creamy, fluid consistency. If your paint is lumpy, resembling cottage cheese, or has a grainy or otherwise off-texture, it is no good.
Disposal of Bad Paint
To prevent contamination of water and other natural resources, paint should never be dumped down a drain or thrown into household trash in its liquid state.
Check with your local municipal waste department for specific guidelines before throwing any paint away. Most allow you to dry the paint and add it to household trash. To do this, simply add clay-based dry cat litter or a commercial paint-hardener product to latex paint and spread the paste out on old newspapers to solidify. Do this in a well-ventilated area, then dispose of the hardened paint in your regular waste receptacle.