I was breaking in(fireforming) some new 45-70 brass today along with some twice fired cases, brought them home and tossed them in the Thumler's Tumbler with nearly a gallon of tap water, couple squirts of Dawn and 1/4 teaspoon of Lemishine. After 3-4 hours they all looked like pewter instead of brass, even the new ones. I feel sure I've used that same amount of "chemistry" before without turning a tarnished color so what could have happened?