Erase and reburn a CD-RW on a Mac

I have been using CD-RW disks on my Apple MacBook Pro, and while I have figured out how to use a Burn Folder to create the disk in the first place, how do I rewrite the disk with newer content without having to buy something expensive like Roxio Toast??

http://www.askdavetaylor.com/erase_reburn_cdrw_on_mac_os_x.html