Toby is right on the ultrasonic. I use granular Spic and Span in water and it works well without harming case color. After the ultrasonic treatment a soft bristle brush, even an old toothbrush, will remove any gunk left behind. Then rinse in hot tap water, blow dry with compressed air, and spray with WD40. Let sit and blow and wipe off any extra WD40. Works great without complete disassembly.

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