Metal Detecting Finds Forum

while metal detecting I found a chunk of something metal….?
someone on the metal detecting forums said that because of the greenish tint to it it could be copper, how could I test to see if it is copper?
put it inside of pool acid muriadic i think it is spelled like that or HCl same thing and if it the acid ‘burns’ off the green then it is copper. Hope i dont ruin ur metal if i am wrong.
My Metal detecting Finds so Far!