So, I used a dash of mineral spirits as suggested to improve the shine
Mineral spirits doesn't improve the shine/polish, it speeds the cleaning by removing the carbon. I would guess it dissolved the carrier wax of your Flitz polish, and this deposited on your cases.
I accidently left my 9mm shells, (about 250) in my tumbler with Walnut and mineral spirits, in for 26 hours. Boy where they shiney, almost blinded me. the walnut was dark and dirty after that run.
I could of just threw it away and poured in more form the 5 gallon bucket i had, but was bored so i washed and dried the walnut and its like new again.
Yep, Lefty. That story is familiar to me. Forget about tumbler and fall asleep. Wake up to blinding brass that's so mirror-like, I can't tell the nickel cases apart from brass. And jet black media. What I realized is that the dark and "dirty" is nothing more than particles of brass and brass tarnish that build up in the media. Take a load of shiny factory new or wet-tumbled cases, run them in a fresh batch of the same type of media for the same 26 hours, and your media will be the same dark and "dirty." The black media will still put a finish polish on cases, but it won't be able to get them clean in the first place. This is why I stop when my brass is clean. If I wanted to bother with a high polish, I would have two sets of media, just like you would use two grits of sandpaper for shaping vs finishing.
If I were to guess, I'd wager that the tarnish is harder than brass. So the black media polish the heck out of already clean and shiny cases. But being the same or less hard as brass tarnish, they hinder the initial cleaning process for dirty, tarnished brass. Same way that red rouge (rust particles) can very slowly finish polish clean iron (and softer tarnished metals), but it can't clean oxidized/patina'd iron, in the first place (if I'm recalling things, correctly, anyway). Car polish, OTOH, has much harder abrasives that remove tarnish and dirt (dirt having a considerable content of metal oxides in it, itself). The more black the media gets, the more you are diluting the harder abrasives in the media.
And yes, this "black rouge" can easily be separated from the media with a few seconds of agitation in just a little bit of water, if you care to. I barely do more than get the media wet, and squeeze out the excess. The black comes away, very easily. YMMV, depending on what additives you use.
So maybe, in one way of thinking, the more you use the media to polish, the more finer (really softer) "grit" it becomes. The very act of polishing is removing brass, which creates brass in the media. This explains why you can take fresh media and turn exactly one batch of brass from cruddy dirty and tarnished to super bling... but then it won't ever do it again. If you set up at least two batches of media, you could get those results for a long, long time. Just don't do any polishing in the first batch. BerettaProf, your shiny case looks pretty polished. To go from dirty to that level of shine, you might find it more efficient to use two or more stages of tumbling. This is something that guys like RC have figured out a long time ago.
Also, new sheets are about $5/100...pretty cheap, adding to my reloading costs....let's see, what's 5 cents divided by 250 cases?
