You may be disappointed to open an old can of paint only to find that the paint has dried in the can. While some people may be quick to simply set the paint can out on the curb with the rest of the trash, you may surprised to know that you can fix the dried paint if it is an oil-based paint. The resulting paint won't be the same quality as the original paint, but it will work well for touch-ups or for covering if you apply several coats. Dried latex paints cannot be fixed so they should be discarded.
Place the open paint can on a plastic sheet to protect your work surface from paint stains.
Pour 1 oz. of paint thinner into the paint can. Use more or less depending on the amount of paint in the can, but it is best to start with a smaller amount and work up to your desired result.
Stir the paint thinner into the dried paint with a paint stirrer or clean stick until the paint is too thick to stir.
Add a 1/2-oz. to 1 oz. more of the paint thinner and stir the paint well.
Continue to add more paint thinner a 1/2-oz. at a time until you have thinned all the dried paint and achieved the desired consistency.