Ammonia will crack the $#*! out of any brass that has been formed or cold rolled. That is, any brass sheet or rod, formed thimbles, patch box lids & hinges, &c.
The 19th century British converted their .577 muzzle-loaders to breech loaders using a humungous brass case. Used them to enlighten the Indian subcontinent. Funny thing happened. Every monsoon season these cases cracked, I believe split down the neck.
Since it only happened in the monsoon season, they called it "season cracking".
Why?
During the rainy/monsoon season the ammunition has to be stored out ot the rain. They did not store it in the officers' quarters, they stored it in the horse barn.
Horses do not use urinals, they use the barn.
It is the fragrant ammonia compounds in the air that crack the brass. These days we call it "stress corrosion cracking"
For the same reasin, do not store your brass near the kitty litter.
Mice, likewise, are untidy little creatures and cause expensive loss of brass valves, etc.
There is ammonia in Brasso. Guess it doesn't hurt in the short time needed to clean your uniform buttons. But those who add a little Brasso when tumbling their brass become very unhappy at the results.
Don't use ammonia on brass.
Jim Kelly, 45 years a metallurgist
