Is anybody aware of a best tool for removing rust & debris from the inside of a hitch receiver? An ordinary wire brush doesn't reach the corners and isn't very quick or effective.
Ideally, what I'd like to see is a four-sided wire brush that mounts in an electric reziprocating saw, but I'm open to all suggestions.

 

I've used a needle scaler before but not everyone has one. Lacking that, I've use a narrow paint scraper to knock the worst of it out then get some Naval Jelly and put it in there with a brush. Rinse it out and repeat if needed. How long is the tube you're cleaning? Is this a Class III/IV or a Class V? Is the tube open on both ends?

We tried to get one apart at a salvage yard I used to run. The hitch had been in the receiver so long, I actually picked the truck up by the hitch to get it to let the truck drop. We finally got them apart with a smoke wrench and hammer.