Interesting question, I appreciate that you asked about something that many take for granted. MLF folks were recommending Dawn as far back as I can remember but never knew why. I use whatever the wife buys and will add a very tiny amount of Pine Sol. Some of the commercial BP solvents now contain citrus, usually orange or lemon. I recently bought a "safe" engine degreaser [Gunk brand] that didn't contain citrus before but now it does. Does Dawn contain any citrus now days? I don't see how using a citrus product could hurt if it helps to break down powder residue. I also use various commercial BP solvents because some built up residue can be really thick and stubborn which depends on the type and amount of powder loaded.