In a pinch you could just breathe on it and wipe it with a dry cloth. Novus #1 is my go to.

Odotb3 is correct, best is novus 1 or you can just breath it.

You can use a cloth with as zeta said windex or light soapy water.

I use Novus #1 as well. It can also be used on the covers (works great on the glossy ones that have become dingy).

I always look at discs i've never watched before playing and usually they are covered in dust and/or fingerprints.

I do three sprays per side with computer monitor cleaner, and wipe with a microfiber towel until dry. This removes both the greasy fingerprints and dust and leaves the disc looking as new besides any scratches.

Just a tip, i'm sure lots of different fluid types would work (record cleaning solution for example)