Today's Aerosol's are crap

Another fun fact. The bottom of can with ball inside is rounded so paint settles on the outside edge of the can. If the can is shaken enough the ball should roll around the outside edge easily stirring all sediment to prevent clogs.
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The point of shaking the can is to get the particles on the bottom of the can to remerge with the carrier solvent. I hold the can around horizontal and shake the can so that the liquid hits the bottom of the can. If there is a metal ball or bearing in the can, then you have to rotate the can, so that the bearing can hit every section of the bottom.