I think the best way to deal with people who use mics is to talk to them and approach them softly.
I often find that the people who enjoy talking a lot (not spamming per se) are often people who are very interested in what other people think of them, provided you are polite.
It is a great opportunity to touch somebody elses heart when you give them the attention they are so desperately needing by perpetuating their voice onto a server, that you can instantly change the flow of a conversation and make it better commentary for everybody.
Younger people are especially prone to this kind of change and I highly suggest that we as individuals attempt to change others with the same kindness we would like to see.