How-to erase a DVD-RW

[Wojciech Puchar]

> iS there an easy way (by cmd-line) to erase a used DVD-RW?
> I tried K3B and can't figure out where to click!

simply don't use "easy to use GUI" just use actual program which is 
growisofs and dvd+rw-format

recording 0 bytes DVD will do the trick, i don't see explicit "cleaning" 
option in growisofs now.

dvd+rw-format will clear DVD+RW disk.