I wonder how long you have to tumble to have that effect.  I have forgotten stuff overnight once in walnut media, to no ill effect.

I recently bought a Frankford Arsenal wet pin tumbler.  It makes a HUGE difference in how clean the brass is.  Shiny and new inside and out.

It would take days IMHO. BUT I don't want to find out! BTW here in PNW I see a lot of food dehydrators. At garage and yard sales. I don't need a second one. Mine stacks 6 layers as I recall and I have not maxed it out. Heck I use it for other parts I wet washed!

Oh, no, tumbling overnight would never over-polish brass such as I described.  It would take much longer, how long I'm not sure, but a few weeks might do it.  Some older people have bad memories and or bad hearing.  I've worked on vacuum cleaners that were allowed to run until the bearings disintegrated.  Older Hoovers with hefty ball bearings.  Let run until the bearings turned to sintered iron.   In one case, only three balls left, shaft very wobbly.  In another case, bearings completely gone, motor shaft wobbling only on the hardened steel races which were quite peened.  At that point, fan interference becomes an issue as well.  You can imagine how a machine like that howls.  But if a person is deaf, it doesn't get noticed.