Aerosol "Brake Parts Cleaner", available at any auto parts store, is a superb solvent for cleaning dirty firearms at about a third of the cost of aerosol "Gun Scrubber" which is essentially the same stuff but marketed specifically for gun cleaning. A word of caution though, Brake Parts Cleaner will strip every bit of lubricant off of metal, so be sure to re-oil your firearms appropriately after use.