Push Stick from an Old Paintbrush
After my paintbrushes wear out, I strip off the metal ferrule with a needle-nose pliers and some strength.
I use the wood or composite handle for a table saw push stick, since I am frequently losing or misplacing mine, I figured it would be better to have more rather than less of these handy tools.
I use a square to measure and mark and the angle I want to cut into the paintbrush. Next, I simply make two cuts on my band saw to make an angled notch in the bottom of the handle.