I have a batch running in a Frankford tumbler this morning - Dawn + Lemi-Shine + SS pins - some pulled down hand loads of uncertain origin - lots of tarnish and some had green corrosion. For first 20 or 25 years of reloading I would put my fired brass in a 4 liter ice cream pail, half full or so of warm water - shot of dishwashing liquid soap and swish the pail around - lots of "black" and grunge gets removed. Drain and onto a big towel - again swish them around - dry in the sun - they are clean - very much clean enough to reload and fire again. Making them "shiny" might be "for the eyes only" - not really can see any performance difference in my hunting rifles. But do not want any grit, etc. on the cases from dropping on ground. Picked up about 250 IVI 5.56 at local gravel pit - all primers were still crimped in, so I believe they were once fired from new - those went into the tumbler - lots of stuff - even insect larva - came out of those!!