Erasing a DVD+RW

I have several DVD+RW discs that I can't erase; I can't erase them because 
the erase program doesn't know it's an RW disc.  Apparently, a program
can't 
erase a disc it doesn't recognize as an eraseable disc.  Rather it thinks 
the disc is a DVD-ROM.

Is there some program that will wrestle a DVD+RW back to the way it came 
from the factory?

Thanks,

Norm Strong