I know how those Game DR things work... you -don't- want one. They abrase the surface of the disc. Useful if your disc has, say, a damn stab wound, but -not- for cleaning. I even refuse to buy games which have been 'refaced' in this fashion.
Use either the soft lens-grade cloth (easily avilable... since they're mostly used to clean glasses) or the lens cleaning paper cloths which are soaked in a solution which gets most things off without undue disc damage. I personally use them on Playstation cds and have had no incidences of damage. Yay!
Basically, most stuff used to clean glasses is okay. They aren't normally caustic, and they're made not to damage items you have to see though, so they normally work okay =3...
I don't know about the writing though. Depends if it's permenant or not. Just be very careful around it!