Black spots on brass. Ideas on removal???

[jeeptim]

Yes I know S/S pins wet tumble will remove dont have. Brass has some black marks from water. Any ideas.
What i do have is two tumblers one with worn out corn cob other worn out walnut shells. I am about to change to a new batch of tufnut. Since i am going to toss the old media (its bad) can i add some goop and pucky to get the stains off?
Was out in the national forest and came across 180 norms cases with the boxes. Gonna load it either way but shinny pricy FREE brass is the best.

 

[Rule3]

Depends on what caused the stains? Tuff Nut by itself should clean about anything. Just use it as is.

 

[rcmodel]

Black or brown stains are caused by enough corrosion the zinc has been leached out of the cartridge brass.

Tumbling with corn or walnut forever will not remove it.

If you want it off?

Polish it off with extra-fine steel wool, and then tumble it.
(Chuck the case in a cordless drill & spin it.)

There is no other way using dry tumbling that I have found in 45 years.

rc

 

[Jesse Heywood]

I have even tried ceramic media without success.
Gun-brite and fine valve grind compound work.

 

[rg1]

A bit of Dillon Rapid Polish 290 on a coarse rag cleans tarnish well. Clean with the rag then tumble in media with a capful or two of the Dillon Rapid Polish added and the spots usually disappear. Also the use of steel wool or a fine Scotch Brite pad before tumbling works too. If the cases aren't corroded the spots won't hurt a thing.

 

[Dr.Zubrato]

Google the nra formula for vinegar, salt, and water. Add tarnished brass and mix until the tarnished parts disappear. Don't freak if the tarnished spots turn a little pink, just take those out and rinse then off well. The pink will tumble out. Pink is zinc being leeched out, but we aren't leaving these in for more than 10-15 mins tops.
Make sure to rinse the cases very well and leave to dry in the sun. Once they're dry (I recommend using deprimed brass) tumble them good and your cases will look brand new.

 

[gamestalker]

Just chuck it up in a drill and use some 0000 steel wool. I do this sometimes, but not because I'm nit picky about how my brass looks. The primary reason I even tumble for that matter, is so I can do a more thorough inspection prior to loading.

99% of the time, Tuffnut won't even touch those black spots, nor will most solutions usually.

GS

 

[Rule3]

Well then, if it is corroded enough to leach the the zinc out why bother??. Recycle it and get some new brass.

 

[BSA1]

I have some new Starline brass with black spots on it. Like yours walnut and corn cob will not remove it. I emailed Starline and their reply is sometimes after using the brass for shooting it will cause the spots to release and clean off.

Otherwise I am not bored enough to polish several hundred rounds by hand .

 

[Rule3]

I have some new Starline brass with black spots on it. Like yours walnut and corn cob will not remove it. I emailed Starline and their reply is sometimes after using the brass for shooting it will cause the spots to release and clean off.

Otherwise I am not bored enough to polish several hundred rounds by hand .

+1 on that.

 

[gamestalker]

BSA1, I have also had those spots tumble off after shooting the brass. I think it just depends on the cause. As an example, I had some Win. .270 brass that did just that after firing it, and some that did not change in appearance after firing and tumbling. So IMO, if the brass looks to be other wise in good condition, I would load it and see if the spots will tumble off afterward, just might.

GS