Re: Q: Cleaning and prepping brass
Agree with David K. for liquid cleaner inside the case, I can't say as I've ever seen a clear-cut case of it happening but it does make some sense.
Myself like David K. I use #000 or #0000 steel wool to get the soot of the case necks, lube them up, and size. No it's not nice and shiny but it doesn't change the group size so I don't see a need. But I also use my brass almost continuously through the year so there not much time for corrosion to build. I do shine up the neck/shoulder/ and the top of the body a little with the steel wool looking for cracks and such.
Also a quick glance at the Machinery's handbook, which is the bible for machinest/engineers I believe 70/30 cartridge brass annealing temp is like 680F. Been many year so don't quote me. There is a transition period where the grain structure starts to change a little before that but can't remember. But it's no where near 200F. David H. I've "dried" many batches of cases just like yourself many many times and no harm. But 2 NOTES: #1 - turn on the oven and preheat, turn it off, then dry the brass. I got in a hurry one time, turned the oven way up and said I'll only leave them in there long enough to get hot. Then the phone rang..... I don't have to finish the story. #2 don't believe the temp on the dial of your oven if you crank up the heat. if you keep in in the 200F region then + or - 100F either direction isn't going to be a big deal. But put a temp gauge in your oven first sometime. I've seen them off by as much as 150F.