Yes, a different solvent would help. Use boiling water. Water is the most universal solvent that exists. Remove the nipples, pour about 1 cup through each chamber, then wipe each out with a couple of dry patches on a jag that will permit thorough wiping of the bottom of each chamber. Then, when the cylinder has cooled to the point that you can hold it in your hand, wipe each chamber out thoroughly with a patch saturated with Birchwood-Casey Sheath. Not only will the Sheath prevent rust (on completely clean & dry metal!!), but it does not have to be wiped out of the chambers the next time you want to load the gun. I hold my cylinders with a baker's insulated mitt while pouring the boiling water through (using a small funnel) and when wiping the chambers dry.

I find that plain, boiling water removes ALL hygroscopic residues from ANY kind of black powder or BP substitute like Pyrodex!

If you use 777, Clean Shot, or GOEX ClearShot powder instead of BP or Pyrodex, cleaning becomes a simple matter of wiping out the chambers thoroughly with plain patches wetted with warm, soapuy water, then drying & applying the Sheath.