Somebody's giving you a bum steer on Hoppe's #9 being bad for aluminum or aluminum alloys. I've been cleaning aluminum alloy framed guns (Star PD, Colt Commander) for well over 20 years and they look like new. Most recently I use Hoppe's on the Ruger LCR. I also use Break Free, Hoppe's gun oil, Rem-Oil, WD-40, a lot of the Outer's solvents and lubes, and various greases. I've used, in areas where I couldn't get anything else, GI solvent, LSA, various motor oils, and transmission fluid. By the way, GI solvent was/is similar if not identical to Hoppe's and we used it to clean M-16s which are made largely of aluminum alloy. There is a lot of mythology on this subject, and it's just that. Fear not! Hoppe's is good for your gun, and in a pinch, can be used as after shave. Besides, it's the #2 smell of freedom, after burnt JP-4.