I purchased a number of Chinese cash coins found in Indonesia that were fused together in a stack, and this Tong Zheng (Yuan Bao) H# 15.35 was in there (its hard to see on the photo, but the character in the east position is Zheng, the only match I can find is this type). I am wondering what way is best to clean/remove the encrustations off of it. I've heard of people using everything from drain cleaner to nylon brushes to clean them, and am not sure how to continue safely, since this is a more scarce type. Coming from Roman coins, of course, I've known cleaning as extremely harmful, and the extent that Chinese coins tend to be cleaned is a little unnerving to say the least. Any input is greatly appreciated as I am still a novice when it comes to Chinese cash.
