I thought I'd ask how folks are cleaning out the trailer hitch receiver. Even though I have mine capped, every spring it seems to have accumulated enough rust to make the hitch tough to slide in. A trailer store I knew of used to carry a 2" square wire brush that was perfect for this. Long T handle, just slide it in a few times and the surface rust was gone. Follow it up with some WD and you were all set for the season.
The store ran out, the manufacturer stopped making them. Internet searches yield me nothing except a patent for it, issued in 2013, but no one is making them.