Question about corroded brass cases

I was recently given about 600 once fired M2 Ball cases from an estate clean up. These were stored in the original 1952 St. Louis Arsenal pasteboard boxes after they were fired (all the same production lot #). Some of the cases had fingernail sized corroded areas on them. I tumbled the brass in my tumbler with stainless steel pin media, which removed all the corrosion. What is left is a black stain where the corrosion was. I cannot see any difference between the cleaned corroded area and the uncorroded brass except for the black discoloration (using a 20X optivisor to check for surface anomalies).
My questions are:
-with the corrosion removed (except for the staining), is this brass safe to shoot?

-do I need to anneal this brass before using it?

Thanks for all replies
Tom

The spots are weaker from what amounts to rust and you may not recover it completely. It may just spot crack there and that's it.

Thanks Jim!
I wont use the corroded stuff, in that case.....I guess I have about 540 good cases. Unfortunate, but hey! They were free (my favorite price to pay for anything)
Tom

I should think you can get brass for .30 cal easy enough around you...

Jim,
No shortage of '06 brass here. I'm just acquiring as much G.I. brass as I can afford for now. I only have about 5000 cases and maybe another 2000 loaded Greek M2 ball. Probably more than enough for a guy my age, but old habits die hard. I'm hoping to compete in some Garand and Vintage Sniper matches this next summer. I'm semi-retired as of last year, and need to make up for the last 25 years of working nights with no weekends off.

I have actually spent more time at a shooting session looking for one lost case, than I had spent the whole time shooting !!! ( a good friend has labeled me a "brass wh##e !:o).
My best,
Tom

Quote:

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Originally Posted by Sgt. Tom

a good friend has labeled me a "brass wh##e

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You ain't alone Tom...I have thousands and have a hard time parting with any of it. Spend an age looking for that last casing.

From one Tom to another you ain't alone. At first I thought I was reading my own post because my friends call me a brass Wh### as well. I have over 5000 rounds of .223 brass and have only ever bought one 50 round box. Over 7000 rounds of 9mm and never bought a box. All range pickups. Oh and Dremel puts out a buffing wheel that cleans that staining u real well. No polish or compounds just the wheel. You get two for less than three dollars and if you use a light enough touch you should be able to clean up around 100 to 150 cases on the two of them.

Tumblers are great for making clean brass shiny.

Brown stains and verdigris are best removed chemically.

Hot wash to remove dirt and other abrasive stuff.
Dump a bunch into "industrial-/ cleaning' grade vinegar.
DRAIN and hot rinse.
Dump into "washing soda solution. "Washing soda" is Sodium Carbonate and can be found in the "laundry" aisle of the supermarket.
Agitate the brass. Rubber gloves may be a good idea here; this stuff is mildly caustic.
When it looks "clean", give it a thorough, hot rinse, shake off the excess water.
Cases may be dried by simply spreading out on a CLEAN towel in bright sunshine, or if not enough of that around, on top of your water heater, near the heating furnace, int the heated linen cupboard or somesuch.

AVOID rushing things by drying in the oven;
a. The kitchen boss may not be sympathetic; NEVER a good thing.
b. it is quite easy to get the brass TOO HOT and anneal the whole case, thus rendering it SCRAP. If the heads of the cases start to go blue, you have probably just wrecked the batch.

I've been using a ultra sonic cleaner. To dry the cases I throw them in a rotary tumbler with crushed walnuts or corn cobs.

I have a lot of HXP surplus and have some cases corroded, and with the black or brown stains. The corrosion comes off easy and is not hard to deal with. The staining does not come off with normal cleaing and does not bother me. I reload it as normal. A couple times I cut through some of the stained brass in multiple locations to inspect. The case wall integrity was sound, the stain was only on the surface from what I could tell with a thick magnifying glass.

I know there are some situations where the powder is deteriorated, the ammo is dangerous to shoot, and the brass may be permanently damaged. That is a different matter, more severe, and I think not the topic of this thread.