First you need a bottle of antiseptic liquid or rubbing alcohol or something similar, nothing too strong mind.
You can use vodka if you want but I think that's a waste of perfectly good alcohol!
I'm using Boots' own brand, there's also Dettol and stuff but I think their own brand would work just as well.
Take your earrings
Next, grab a cotton pad/ball or whatever you can find and pour some antiseptic onto it. It actually smells quite nice, like mouthwash.
And just clean away!
And you will have yourself some damn clean, germ-free earrings.
Ps, I don't know if you can use antiseptic on gold. Though I think silver-plated is fine.