Re: Cleaning brass
Years ago the NRA published a 'facts book'. They recommended citric acid as the safest and most effective brass cleaner. I tried dampening my media with vinegar, and later, with non-ammonia window spray, and when I could find the kind that included vinegar, I used it too.
I've found that lt all works very well. I have also used diluted CLR as a dampener, and it's very good.
Couple of points. Rinse the brass afterward. I tumble it in dry media to dry it off inside and out, and to prevent water spotting.
Dampen the media before you add the brass and run the damp media by itself until the dampener is completely absorbed. Otehrwise, the medium will get inside the brass before it finishes expanding and become impacted in there.
If you leave the cleaned brass overnight in the CLR dampened media, tumbler off, it will acquire a dull olive patina that is fairly durable, but which will come clean with more tumbling (a lot more, but it <span style="font-style: italic">will</span> eventually come off). Some folks will find this to be a very interesting phenomenon.
If you intend adding abrasive, try jewelers' rouge, and be sure to get it all off before running your brass through the dies. Otherwise, it will increase die wear exponentially.
Greg