What is the best thing to use to clean DVD's?

On my Nightmare Before Christmas DVD, there seems to be just a bit of something on the DVD and I want to know what would be best to use to clean it. It isn’t scratches, it’s just more like, a suppose you could call it a smear of something, lol.

Rubbing alcohol has worked for me. It takes off any “sharpie” mistakes on the front and doesn’t seem to harm the data side.

Warner Brothers (New Zealand) FAQ to Cleaning DVDs