Actually, BP is not very corrosive at all. It's fouling is, but the powder, not really. It will be compacted and stuck together but getting it out is not going to be that hard if you have a breech face scraper. However, it is also easily "dissolved" with water. Water is a far better solvent for bp than any oil and you will be able to remove it in a minute or two. It would be interesting to see what that powder looks like if you get it out dry.

If you have a half decent gunshop near by, you might find they have a "worm" such as Stan described and a scraper that will fit an 8 or 10 by 32 tpi cleaning rod. For a few bucks, it would be worth it. You don't need a shotgun gauge-specific one either, though that would be nice.

Eventually however, you will be well served by scrubbing the breech with water and patches on brushes, drying, using WD40 to assist with that and then oiling as per normal.

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BrentD, (Professor - just for Stan)
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