Niels Berkers asked:

> Is there a way to clean the threaded rods without damaging them?

I fixed this problem by using WD-40 spray, and wiping with paper
towels, to get the easy stuff, and then spun a leather nut down and up,
a little further each time, with more spray and paper towels wipe;
eventually it worked easy, and the towel clean.  Works fine for plastic
jams, rust, tar, and most I've encountered.

Will Herzog