I am SOOOOOOOOOOOOOO cheap!!
When I fertilize my lawn I save a piece of the bag because it's extra thick
plastic. Cut a square about 8 or 9 inches. Hold it centered over the ball
and fold down the sides. Secure with a rubber band.
If you want to get real fancy you can cut off the corners and make
it stop sign shape.
Also potting soil comes in heavy bags.
I used to use a folded up WalMart bag (still do in a pinch)
but the square of heavy plastic bag works better.
It keeps the grease on the ball and off me and keeps dust or road
grit off when I'm running around with the hitch on there but no trailer.
When I'm towing I can fold the plastic and put on the rubber band to
keep it greasy side in and just toss it in my front storage hatch.
Cozy's are for keeping the beer cold!