ya, i've read that you can crush them, microwave them, or cut them out and toss them, if you can find it. they are 1/3 of a millimeter.
Just so everyone's clear - do not go sticking body parts in a microwave. RFIDs are small and getting smaller. They can be used to track things, but in no way can control your behaviour. So, even if you do have one implanted, all "they" will know is where you are when you pass within a certain distance of a reader.