If you don't have an air compressor you can always buy that air-in-a-can stuff they sell for blowing dust off of electronics. They sell a 3-pack at my local Office Depot and that's part of my cleaning kit. When I go to clean off my solvent, no matter how good a job I do, that strong compressed air manages to blow a micro-thin layer of it off the metal.
As you use it the can will get cold. As the can get's cold the pressure goes down and it won't blow as well. Run it under hot water to solve this problem.
I've also used WD-40 (followed by solvent and then compressed air before using REAL gun oil) with good success as a de-greaser/cleaner for my gun parts.
Your 9mm could, and in all likelihood will expand. But my .45 will never get any smaller.