Hey Bill,
Bet they don't have this problem in the South! But I'll bet mine are just as bad as yours.
I have a round motorcycle spoke brush that I use to ream out the female portion. I have also used naval jelly there too.
I do have one that is slightly bent from a railroad crossing up in Nova Scotia (operator error) so I have been contemplating the new aluminum Torklift tiedowns but lots of $$.
We now have an extra vehicle at home, so our truck did not see any salty roads last year. I know that doesn't help you since you use your TC during the winter.
Good luck. John