Even jewelry you pay more for can have the same effect<, because the expensive metals aren’t completely pure<, regardless of gold or silver content. Platinum rarely reacts with skin so no worries if you own platinum jewelry. To try to stop gold jewelry from making your skin green make sure that you don’t have made from cheap metal and then plated – its a cheaper metal with a thin gold layer that can rub off. For ‘real’ gold jewelry spending the extra on 18 karat gold only can help reduce the marks that are left on your skin.
Jewelry made from copper will also turn your skin green and you’ll have to just accept that if you wear copper.

Try to avoid sweating in your jewelry it can amplify the skin to metal reaction you might also ask your jeweler if they can add a layer of protective coating – in order to try to stop the reaction or minimize it. If you do this you can keep wearing your base metal jewelry without worry. Don’t forget~ your skin turning green is a harmless reaction. It’s just a skin reaction and not allergies.
Allergies will causes reddening and also will make your skin inflamed and itchy. It’s not anything like green skin. If you do show signs of allery stop wearing the jewelry. Green skin shouldnt scare you ore keep you from wearing your favorite pieces you may just have to clean your skin more so its not ugly.

All in all coating it is usually the best option.