If I used them at all I'd probably use alcohol on them (rubbing alcohol). Lots and lots of alcohol. That's what I use on everything.
Personally, I find them about as disgusting an item as it gets. People use them and then leave them around, and then put them back in their ears - the two-way, disgusting, cycle, goes on and on.
I've had a couple of things come with ear buds; and even if I didn't plan to use them, they'd tend to end up on the floor for some reason. When they have, I've washed them under running water, with soap and dried them with a paper towel. They "lived". I just made sure the opposite end of the cord they were on didn't get anywhere near any moisture.