Erasing a Rewritable CD (CD-RW)

So, I have a few rewritable disks that I like to use to burn my music to - mainly because they are in fact "rewritable." However, now that I'm using iTunes to manage my music, I don't know (a) how to record the music on disk so that it plays AND it can be erased later, and (b) how to erase the music at all. My rewritable disks don't serve much of a purpose if I can't "rewrite." If someone could help me out, or at least let me know if this is even possible or not, it would be MUCH appreciated!