How to Determine When Paint Is Too Old to Use?

Ask yourself when you purchased the paint and when you opened it. Most unopened cans of oil-based paints are good for 15 years and unopened cans of latex paints are typically usable for 10 years. Opened cans of paint are typically good for two to four years after their initial opening.

Look at the consistency of the paint. Old paint that has been frozen and refrozen several times will often become chunky. Sand-sized chunks and grit that have occurred from slight freezing are often removed from the paint by straining it through nylon or a paint strainer. If the chunks are larger, however, the paint isn't useable.

Attempt to stir the paint if it has separated. Over time, the materials in the paint will begin to separate from each other. If the paint blends again upon stirring, it is still usable. If it still remains in layers, it is too old to use.

Smell the paint when you open the can. If the paint smells like anything other than itself, it is too old and should be thrown away. Bacteria, mildew and other material can enter cans of paint if they sit around too long. In addition, adding water to the paint will also introduce the harmful agents. Paint will begin to smell unpleasant when it is contaminated.

Look to see if the paint is dry. If the lid wasn't closed on the can properly, air can get inside and cause the paint to dry out. If a skin has formed on top of the paint, remove it with a stirring tool or paintbrush and check to see if the paint is smooth underneath. If so, the paint is still usable. If not or if the paint has chunks, it is too old.