Use "Scotchbrite" name brand cleaning pads. The green ones are best, but finer can be used. The green ones you can buy in a grocery or hardware store. The other colors are sometimes available at Lowes or Home Depot, or an automotive paint supply business.

Take a used bore brush, .22 works well, and cut a small piece of the pad to wrap around the brush so it will fit tightly in the chamber. Mount the brush in a drill motor and spin it in the chamber using some oil as a lubricant.

It won't take long and the abrasive in the scotchbrite is not agressive enough to remove metal. I wouldn't recommend jmoore's suggestion as you could distort the chamber dimensions. The scotchbrite will "dig"into the pits and clean them up, and it will polish the smooth chamber sections at the same time.

If that doesn't do it, the chamber is ruined.

Good Luck!!

HTH,

Emri
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