I'm trying to clean up the threads in the nuts in my nut strip on my 2000 Cherokee. I tried using a round brush to remove the dirt and rust. Didn't do much. Tried a trhead chasing tap, could't even get it to start in. Tried a regular tap could bareley get it started and then couldn't make any further progress. Looking for any idea on this problem also in removing the rear bolt that holds the tail pipe bracket. I'm about to give up on trying to install the hitch.