Been using Windex with vinegar since i got back into blackpowder about ten years ago. Windex with vinegar is less than five percent vinegar and it will not harm your gun. It eats the residue and crud left from firing 777, Pyrodex, Black Mag III, Pinnacle and back powder. i also use Windex with vinegar to swab between shots when using Pyrodex and 777.

Wet a rag or paper towel with it and you can wipe off the crud. Sometimes you can see the fizz as the acid in the vinegar eats up the base in the powder residue.

Mike Venturino, the former black powder editor of Shooting Times magazine, got me onto Windex with vinegar.

The SASS guys use it.

http://www.curtrich.com/frontiersmen3.html

CLEANING:After each stage wipe off the front of the cylinder and the hammer, hammer notch, and nipples with a shop towel. If fouling around the hammer is dry and crusty, then use a shop towel wetted with Windex with Vinegar and water. If, using American Pioneer Powder, Pinnacle, or 777, you need bore cleaning between stages, something is wrong.
At the end of the day take the cylinder out. Spray it with Windex with Vinegar. Clean the nipple area with the toothbrush. Personally, I never remove the nipples. Instead I clean the outside of the nipples with the toothbrush, then turn them 180° with a nipple wrench and repeat, then retighten. Don't lube the cylinder. It's stainless. Dry it. Toothbrush fouling off the frame after dousing with Windex/vinegar. Clean and lube the base pin with lubricant of choice. Run a Bore Snake through the bore (Windex on front end, lubricant on back end). Lube with lubricant of choice. Reassemble.