I have read every single post in this thread. The only question I have seen by the OP is should I tumble longer? My answer is that tumbling is not needed at all. But if you do it and crumbs remain inside, either clean them out, or don't, it doesn't matter.
Its not really needed, for years we never polished our cases. It does look prettier tho when polished.
Does it put extra wear on the sizing dies when you dont clean the brass first?
If carbide dies not in your lifetime. Clean the cases of course. Polish, not so much needed.
Frankly I polish my cases after depriming and resizing, that's hand gun cases using carbide dies. Very doubtful you'll ever wear/scratch carbide dies, they're just a step down from diamond.
The table below incorporates additional substances that may fall between levels:
Noob here, how would one go about cleaning a case if not to tumble?