At this time we are only monetizing beats- i.e. instrumentals without vocals (with the exception of a hook, assuming the hook is not sampled from a song).
As you must own 100% of the music submitted for monetization, submitting songs, in which an artist may own the lyrics/vocals is not currently permitted.
If a song is uploaded as beat and submitted for monetization, it will be removed from Content ID without warning. (This does not affect your store)
Content ID is available to Platinum members only. If you have a free account, you can upgrade here.