I have a couple DVDs that I've only viewed a couple of times and put back in their boxes, but are now unplayable because they somehow got dirty or scratched somehow. No point bitching in how it happened, so how do I fix the problem? Usually, I just use a soft cloth and clean from the hub out to the edge, but that didn't fix the problem with these DVDs. I've heard that those "DVD Doctor" and other products aren't much of a help and sometimes make the problem worse. So, any suggestions?