Thank you very much for your response. I appreciate your time!It can also be said that by the time the Germans began using Gas, the Brass Helmets were pretty much phased out, and the Pickelhaube was on its last legs as a useful helmet anyhow, because by the time Germany realized gas as a more mas weapon, it was already being phased out in favour of steel helmets.
That being said, while I think you MIGHT be able to find an M15 with some minor corrosion from a type of gas, it is unlikely, and I doubt that would find a Brass piece with Gas corrosion.
Hopefully this is some helpful input.
Thank you very much, I appreciate your time.Gas is corrosive. Look at a WW1 gas mask filter, especially German ones (because they were picked up on the battlefield and therefore actually used) , they rust from the inside out due to the gas trapped in the filter - as it's supposed to be.
Having said that, I don't believe oxidation on brass spiked helmets has anything to do with gas. Any gas on the helmet would get washed off in the next rainstorm. The oxidation is simply due to age.