I bought several sizes when they first came out (many years ago). I recall using them one time (don't even recall on what), but based on everything I have read and heard, will never use them in the future.
I am always able to remove leading, carbon fouling, or any deposits with alternative means that are less aggressive to the bore. If I had a barrel that had severe pitting and I wanted to remove the corrosion deposits, I might consider using them. But for anything less, it just isn't worth the risk.
I do soak the cylinder or barrels overnight with Ed's Red, and that really helps loosen the deposits. Between a copper Chore Boy, Lewis Lead remover, or oversize bronze brushes it comes out. Once things are clean it is much easier to keep them that way.
