Screen Cleaner

Clean your Apple products - Apple Support

"Use a cleaner intended for use with a screen or display. Never spray cleaner directly on the screen. It may drip inside the display and cause damage."

There is an issue of stains occurring on the screens of Retina displays:

My Retina Display has stain damage, HELP!!!

and others. My feeling is that it's caused by outgassing, oils or acids.

Presented without recommendation:

http://www.amazon.com/ShaggyMax-MacBook-Retina-Screen-Protector/dp/B009D7GQ04

Well I don't think that's necessarily the case but you should read the ingredients carefully.

You'd always be safer using Apple approved products:

http://store.apple.com/us/mac/mac-accessories/device-care

Especially if it's a newer rMBP, still under warranty or AppleCare.

I have used Windex Electronics Cleaner in my MBPs for at least the past six months+ with excellent results. The displays look like the day the unit came out of the box. I use a small microfiber cloth dampened with the product to wipe onto the display and a large cloth to wipe off the residue.

http://www.windex.com/en-US/Products/Pages/electronic-cleaner-and-wipes.aspx

DO NOT CONFUSE THIS WITH ORDINARY WINDEX GLASS CLEANER.

Ciao.

Follow Apples own advice…

Clean your Apple products - Apple Support

edit: turns out this page needed refreshing, excuse the duplication.

From that same site:

Don't use aerosol sprays, solvents, abrasives, or cleaners containing hydrogen peroxide that might damage the finish.