I have the new mabook aluminum unibody etcNow i know the new screen is glass/arsenic freeSince it's glass can't you use windex on a paper towel and wipe?
You should be able to just clear itI personally like to use surface cleaner and prep from Arctic Silver, stuff is amazingGot mine from neweggYou can just leave that thermal pad there if you want and just grease it as well.
It's preferable, but if the old grease was still gooey and you didn't loose any, you'll probably be okIf the old grease was hard or rather dried out, it would be best to use some new stuffThe grease is what conducts heat from the processor to the heatsinkThe more powerful the processor, the more heat it generates and the more important it is that it make a good thermal connection.
I just use a microfibre cloth, very very slightly dampI use it on the whole macbook and screen.
