Blue Brass?

[JCherry]

My son has a couple hundred pieces of .40 S&W brass which has some bright blue spots on it. He describes the spots as being about 1/4" X 1/2" and said they are on the outside of the brass not on the inside. The blue will rub off but leaves a "stained" spot where it was. He said the brass was very shiny when he got it in a trade about 10 months ago. The brass has been in a basement which apparently can get a bit humid, he is in Minot, North Dakota. Other brass he has stored in the same area does not have any blue coloration on it.

I have not seen the brass but suspect it may have been tumbled with Brasso or some sort of ammonia etc. and combined with the humidity has caused this blue coloration.

Has anyone else encountered this type of blue on Brass? Can it be cleaned to remove the blue spots?

I'm inclined to tell him to discard it as the ammonia may have weakened the brass.

Have Fun,

JCherry

[Tom Herman]

That would explain the blue color (copper compounds).
Tumbling it should remove the blue. I don't know how bad the corrosion is. You may or may not be able to get rid of the tarnished areas once the blue is gone.
Hopefully someone else can chime in and give you an opinion on the strength issues.

Happy Shootin'! -Tom

[rockrat]

I have also heard that ammonia will weaken the brass and it should not be used.

[oneokie]

Was the brass stored in a cardboard box?

The residual chemicals in cardboard will cause the symptoms you describe.

[shotman]

as cheap as 40 is i would nt waste the time They sell for around 30 a 1000

[legend]

i have tumbled with brasso for 30 odd years,never had the problem you describe.