I'm no expert but I think I can help. I just did a bunch of cases. Several loads. I've been experimenting. The reason the cases have wet media in them is because you didn't mix it 1st. Also the mineral spirits is important. It's a great mild solvent and gets the black off. It also thins the NF so it gets absorbed by the media. If my cases don't polish in a reasonable time then I need to add more wet mix.
I use lizard litter. Ground walnut shells. I fill my hopper about 2/3 full. I then take an old cat food can and add 1 cap Nu Finish and 2 caps mineral spirits and mix them with a popsickle stick. Then I pour this around the media. Close it up and run for 15 minutes with no brass in it to mix the solution with the media. This is important. It keeps the media from getting wet clumpy spots. I then take 2 dryer sheets and cut up into little squares and add them to the media. This cleans the media they say. Sure seems to. The black soot sticks to the sheets. Then add the cases and start tumbling. A couple of hours usually does the trick. Not just to clean but super polished.
I've found that if they aren't coming clean in a couple of hours then either run some more or I should have added solution to the batch. When I run several consecutive batches I'll add more solution at least every other batch. If I don't then it takes much longer to polish the last of the soot off. The MS evaporates away slowly.
The only batch that had clumps of media in the cases was the last one I ran the other day. I failed to pre run the mix in the media and just added it with the cases.
Every other batch I remove the dryer sheet pieces and replace. I run a max of about 2-300 44 mag cases or 100 45/70 at a time.
I takes longer but I sit down at the bench and wipe each one. I just pull a couple at a time out by hand and tap them out and place on a rag towel until the hopper is empty. This removes the stuff inside. Once the hopper is empty I sit down with another rag and a 44 bore mop on a pistol cleaning rod. I pick up each case and tap it on the table open side down. Run the mop inside and then wipe and drop the shiny case into a plastic container and repeat for all the ammo. I figure it's probably not necessary but they sure come out purdy and I have no issues with media left in the cases. I figure this also removes any residue from the solution that might later cause a problem. It takes a little time but not bad really and the results are ammo that looks as good as the Henry I'm putting them in.
I have run probably 3,000 cases through the media in my hopper and will probably replace it soon. I was thinking of putting some of the old stuff in a small can as campfire starter. Mineral spirits impregnated walnuts shells outta burn pretty well!
These pics are with the old camera earlier in the year when I was just getting started. The last round I did last week came out looking like the receiver on my BB. I'm getting better at it.
I know shiny cases aren't needed. But like so many things when you are done the finished product looks like you really accomplished something. I don't shoot so many rounds that I can't take the extra time.
Hope this helps.

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