Q: I have a few smudges on my screen how do I clean them?

I would try a cleaner used for windows, they usually work quite well. Just be careful! You should only put a little on a cloth since it's liquid.

Here are some notes on cleaning Apple products in general.   There is a section for the screen.

How to clean Apple products

There are many cleaning agents for glass; some may do less damage to a screen than others but in general you should follow Apple advice ... particularly if the machine is still under guarantee or Apple Care.   Using the wrong cleaner could invalidate your cover.

Get a CLEAN microfiber cloth (preferably a new one rather than one that has been used for something else).  Dampen it SLIGHTLY (should not be able to wring out even a drop) - I use a fine spray and spray the cloth NOT the screen.  Gently wipe the screen and polish gently with a dry part of the cloth.  Should be all that is needed for fingermarks etc.  NEVER use alcohol, solvents or other chemicals.

Apple used to supply a fine black microfibre cloth; it was excellent.   But it needed only water.   Any other kind of agent, be it in spray or liquid form, is not approved of.

Go to the Apple Store. They have some screen cleaners over there.