Unopened Cans

• Unopened cans of latex and oil-based house paints for interior or exterior use have a basic shelf life of two to five years. Some manufacturers, such as Glidden, suggest a two-year shelf life, even in ideal, climate-controlled storage conditions.
  
  

Opened Cans

• The shelf life on an opened can of paint is shorter than that of an unopened can of paint, much like other opened vs. unopened products. An opened can of paint's shelf life will vary greatly depending on how well you've resealed the container. Place plastic wrap atop the paint to keep air out before resealing the can. Wipe any drips from the rim area before placing the lid on the can. Tap the can lid closed with a hammer or step on it. These techniques will help prolong open paint's shelf life. If there is only a small amount of paint in the can, pour the paint into a smaller airtight container such as a jar with a screw-top lid.
  
  

Storage Conditions

• Where you store opened or unopened paint cans affects the shelf life of the paint. A can of paint that has been kept in a garage, freezing in the winter and getting hot in the summer, will have a shorter shelf life than paint stored indoors in a moderate environment. Keeping paint near a hot furnace or in a humid area, especially if the paint can has been opened, will shorten the shelf life as well. The ideal storage area is a cool, dry area with little long-term temperature variation.
  
  

When Not to Use Old Paint

• It may be tempting to use old paint for touching up areas that need a fresh coat, especially if you have half a can of the perfectly mixed house color on hand. Before using the old paint, inspect it for less-than-ideal characteristics. Paint will settle and separate a bit if left unused for long periods of time. When stirred, paint that does not blend into a smooth, consistent texture and tint may have gone bad. If the interior bottom of the can has rusted and contributed rust bits to the paint, do not use the paint. Paint that seems overly rubbery or hard even after extensive stirring may not spread well and must not be used.