What makes it green? Any way to clean this? It looks so much like old Chinese pottery.
For your first question. Your cymbal is oxidized, and the green color is called patina
Initially, bare Cu metal atoms react with air to form the pink oxide, cuprite, Cu2O, which has Cu+1 cations. This gradually oxidizes further to the black oxide, tenorite, CuO, with Cu+2 ions. The black sulfide CuS also sometimes forms. In the presence of moisture, the blackish layer slowly reacts with sulfur dioxide and carbon dioxide from the air to eventually form the patina, which is a mixture of 3 minerals:
brochantite, a green, hydrated copper sulfate, Cu4SO4(OH)6
malachite, the green, hydrated copper carbonate Cu2CO3(OH)2
azurite, the blue, hydrated copper carbonate Cu3(CO3)2(OH)2
To clean it, you could search using keyword
clean oxidized copper and choose one that is appropriate to you.
This cymbal is an alloy of copper and tin. The green coulor is the a phenomene of the oxidation of copper. It can be cleaned and will disappear by a chemical reduction with hydrogenium.
the link of wiki says:
From Wikipedia, the free encyclopedia [wikipedia page]
Cymbals are made from four main alloys, all of them copper-based. These are: bell bronze, malleable bronze, brass, and nickel
How to polish:
Also look up Youtube tuorials:
I don‘t promote one product as it could interpreted as advertising.
But this point had to be added:
The question should be answered not with advises how to clean a cymbal. More helpful would be how to avoid this oxidation: The cause is the humidity. Keep your band room dry.
I hate to break it to everyone but, this is not oxidation at all... Yes, copper-based oxidation is green and occurs for all the reasons stated but, it's also (9 times out of 10) highly localized and crystalline in its formation, even in the worst cases. As pictured here:
What is pictured in the OP is a cymbal that is covered with too much cymbal polish that has dried, like 'lizard spit'... The 'finger-swipe' marks give it away (I have seen this done by an amateur before...)
With very minimal research, I was able to confirm this... The picture in the OP is a screenshot from this YouTube video:
22'' Zildjian A with green goo (Part 1 - BEFORE)
Part of the video description:
My first experiment with artificial aging of a cymbal. Both cymbals sounded very similar before the mixture was applied. I wanted to try to reduce some of the wash. The junk dried up the sound substantially. The process took about 7 days. Ingredients are common items found in a kitchen. Lemon juice, flour and plastic bag. The cymbal was rubbed with lemon juice and flour and left in the bag for 7 days. Then it was taken out of the bag and left to dry for 2 days. The video was taken on the second day. The green goo dried the cymbal up to the point of choking it. I later removed the green goo by washing the cymbal in lukewarm water. Although the green goo went away, the cymbal retained some leopard print tarnish that darkened the sound without choking it as much as the green goo did. See Part 2 for the results of the removed goo.
Going on the assumption that @Maika_Sakuran0miya did not post the YouTube video (otherwise positing this question on the SE makes ZERO sense,) I think the OP is having a bit of fun at the community's expense with this one...
So... the correct answers to these specific questions (at least in this one instance) are:
What makes it green?
Too much polish that has dried on the cymbal.
Any way to clean this?
Yes, wash off the excess polish.
Yes oxidation, and all the scientific stuff everyone was mentioning. I have seen sweat, spit, and assortments of alcoholic beverages turn cymbals into this color. Essentially moisture and air as I believe a few have said.
To clean it all you need is some Brasso (or comparable metal polish), a cloth, and some elbow grease. Take your time, work in sections and wax on, wax off till you get the shine you want.