Submit portable freeware that you find here. It helps if you include information like description, extraction instruction, Unicode support, whether it writes to the registry, and so on.
Download the installer from here
Decompress the installer with Univ Extractor
Get EraseDVD.exe from MAINDIRECTORY (or something like that)
Erase your DVDs, put them back on the free stack
Major burning software may already know how to erase rewritables, but it's ~600KB, so it's no big deal.