I'm not sure what you mean, but CD-RWs are reusable. If you have a collection of 10 VCDs on your computer but only 2 CD-RWs, you could theoretically watch each of them in order, buy burning one at a time (or 2 rather, since 1 VCD movie usually takes up 2 CD's) and then use your burner's format utility to erase it (I think Nero has one built-in as well... it's just a function on the burner, every burner should have it).