As paint sits in storage or your inventory, the contents in the aerosol will settle to the bottom of the can. If not shaken thoroughly, the contents of the can have not been thoroughly mixed well enough. Before use, shaking the can thoroughly for at least 1-2 minutes after the agitator ball inside the can begins to rattle, is essential to achieve the desired color and gloss outcome. Periodic shaking while spraying is a key component to proper aerosol usage and proper color and gloss results.