one guy I met at a range, was 'cleaning out' an old rust bucket by shooting it!!
He had done all the scrubbing, but was still intent on getting more of the junk out. He was lubing his patches with ?topal? tooth paste.. Some kind of slightly abrasive tooth paste used for smokers to whiten their teeth.. ( what he told me it was used for
anyway, he figured the light abrasive.. would scrub out the bore as it shot? Never saw him again to confirm, whether or not it worked? Later on a read through all the articles about 'Fire lapping" bores.. Same basic idea, harsher compunds is all..
For what it's worth?