Need advice for cleaning dirty brass, very dirty brass!

[caporal]

Hi everyone

I guess it have been discussed elsewhere, if so please redirect me!

Here the facts. I'v got over 2500 9mm brass pick-up at firing range. Most of them have spend 1 or 2 years on or in the ground.

I Remove dirt, grass & mud from a sample of 100 or so of these by tumbling them in water & let them dry in the hot last summer days. Result, there is no signs pitting or blueish/greenish corrosion on them, but most are seriously tarnished & have a dark brown/kaki patina.

what would be your recipe/advice for polishing them.


Thanks

Larry"Corporal"Marcotte

 

[tigrr]

The ones that look like they have been painted with army dull green/brown paint really oxidized copper, chuck they are only going to split anyway. The ones that some brass is showing through and is shiny keep and polish.
A polisher with 3 parts corncob and 1 part walnut shell will clean the shiny ones up in 6 – 10 hours of polishing.
After shooting once check to see if any cracked.
I have a pic of cracked dull ones I will try and post later, see the 4 cracked ones.

 

[CyaN1de]

I use Walnut media with either Lyman Turbo Polish or an Aluminum Mag Polish (much more effective). 2-3hrs in the tumbler.

Since the Mag polish has a bit more abrasiveness to it, it really does a nice job on the hard to clean brass and makes it look better than new. If the water stains (black) are really deep into the brass, it will not remove all of it but it should not be a problem as it is only aesthetics at that point.

I put more than the prescribed Tablespoon for the really grimy stuff, anywhere from 2-3Tbl/load

 

[(((Echo)))]

Had a similar deal with mine. Tumbling would take forever with the amount I had, so others on here suggested using CLR in a tub of water.
I dumped the brass (~2000 cases at a time) into a tub, filled up just past the brass with hot water and added a couple of cap fulls of CLR. Stir (with a stick or a gloved hand) and let them soak for a bit. You do NOT need a lot of CLR when doing this. I let them soak for about 1 hour and then rinsed well and let air dry. This removed most of the tarnish and gunk. They weren't shiny like they came out of a tumbler, but I could see if any were junk. Any of the cases were still heavily tarnished were tossed.

(E)

 

[stovepipe699]

Tumble them in walnut media(lizard bedding from pet stores) with a little Nufinish car polish worked for me.

 

[kombayotch]

Wet tumbling with ceramic media will make them look like new.

http://www.bpcr.net/site_docs-results_schedules/documents/ceramic-bead_polishing.htm
http://www.bpcr.net/site_photos/ceramic_bead_cleaning/index.htm

 

[BattleRife]

I soak tarnished brass in a solution of 3-5% phosphoric acid. It is available from hydroponics, pond and homebrew stores. Triple rinsed and followed up with my normal tumbling program (1 hr in treated wlanut then 15 minutes in plain walnut) and they shine like new.

 

[sillymike]

Maybe it's just me... but it sure sounds like a whole lot of work when 9mm brass can be found at gun shows for $40/1000...

Because after cleaning them, you will still need to;
- Find which ones are berdan primed
- Find which one have crimp on the primer pocket and either toss them or clean up the crimp...