Paint stores have a machine that shakes paint thoroughly. Paint that sits for months settles and congeals, making it impossible to paint with. Paint that sits in storage in your home must be thoroughly mixed before use. You will be able to do this on your own, although stirring it by hand will take longer.
Things You'll Need
Thin steel rod
Bend a thin steel rod into an L shape. Insert it into an electric drill instead of a drill bit.
Plug in the electric drill and insert the rod completely into the paint. Turn the drill onto low and hold the drill still. Work on a covered surface, or outside, to prevent making a mess if you slip. Mix the paint with the drill for several minutes. Turn off the drill before removing it from the paint. Save the bent steel for later stirring use.
Stir the paint by hand with a wooden stick to completely distribute the paint. If you see any chunks or there's a watery texture on top of the paint, repeat stirring with the electric drill.