This bears repeating, so I'll say it again,
And keep in mind that I tumble brass on an industral scale, so longevity of media & an efficient process are key...
First off,
Walnut & Corn Cob are POLISHING media, NOT CLEANING MEDIA!
THE OLD SAYING OF "GARBAGE IN = GARBAGE OUT" APPLIES PERFECTLY HERE!
*IF* You want to waste your media's effectiveness, then by all means drop that sticky, gummy, greasy powder residue brass in the POLISHING media and plug up the polishing surfaces!
If you want to do things CORRECTLY & QUICKLY (emphasis on quickly, time is money),
Then use a SOLVENT to clean off the sticky residue!
(Like the solvent you use to get the same sticky crud out of the firearm!)
WASH THE BRASS!
Dawn & water will do that job in 5 minutes, an acidic hard water additives or detergent will do that job in 2 minutes.
The only 'Specality' tool needed is a sealed container, pickle jar, coffee can, etc.
Spin/shake the water out of the brass, the very small amount of moisture the brass carries into the dry media will work as dust control without clumping, particularly with walnut shell media.
*IF* your media gets too wet, 20 minutes in the oven at 150*F. will dry it out again...
Second,
'Dust' is crud from the cases & media breaking down.
Dust is dangerous to breathe.
ANY small particles (dust) is dangerous to breathe, more so with gunpowder residue.
Without ANY specialized equipment, other than a damp rag over your face if you aren't smart enough to get UP WIND of the dust,
You can simply spread out a sheet, towel, tarp, etc and pour your media from one container to another.
The dust being lighter, will drift off from the granular media.
Dust control is as simple as a misting squirt bottle (like an old Windex bottle) or a USED dryer sheet.
Adding SMALL AMOUNTS OF MOISTURE (water) to the media hurts nothing, and controls dust.
A few small sprits from a squirt bottle stops dust issues. Period.
THIRD,
Common sense...
Clean media works MUCH faster than old, plugged up media.
Cleaning off the greasy crud first saves a crap load of tumbler time.
Tumblers cost money & wear out. The LESS tumbler time you have, the longer the tumbler lives.
The cleaner the media, the faster it works & gets replaced less often, saving time & money.
The point here is, you work for money, that saves you time at work for media & tumbler cash,
And it speeds up the reloading process so you can shoot more for less money over all.
This is the 'Dollars & (common) Sense' end of things...
Walnut shell media can be cleaned, but that also takes time.
The best 'System' is to wash the brass with a grease cutting solvent FIRST so you don't plug the media up!
A few drops of detergent & water are CHEAP, but the TIME you save is priceless,
The brass POLISHES faster, and you don't spend time cleaning media...
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And now, rebuttal by guys arguing AGAINST common sense because they don't do it that way.... In 3, 2, 1...