Matt, if you clean and oil properly, soap and water is a very good option for cleaning BP and T7 and Pyro. Been cleaning MLers for more years than most you fellas have been alive with soap and water. Always use HOT HOT HOT water. The hottest you can tolerate. Makes evaporating and drying the water 100 times easier. I use that Otis stuff only every so often. No need to use it for every cleanup. Since I went to Blackhorn I now use Hoppes on my PH BP barrel but I still use soap and water on my old Hawken. Never had a rust issue with any of my BP firearms. Light coat of oil after cleaning and drying and all good.