When painting from a gallon can of paint, it is common to wipe the brush off on the edge of the can which results in the lid groove filling with paint. I would guess everyone has accumulated one of the cheap plastic pouring lids that snap on the bucket. I then had the idea to drill a couple of holes in the plastic, bend the ends of a coat hanger wire 90 degrees and snap it into holes across the lid. This gives you something to wipe the brush off so that the excess paint falls back into the can. Make sure you place the wire near the back of the lid or else you will get paint on the back of your hand every time you dip a brush into the paint. The wire snaps out of the plastic for easy cleaning.
It works great, and is cheap!