Novus 2, and elbow grease. Unless the dirt is ground into the clear coat.

LTG : )

novus 2 works great for the playfield.

There is no schedule. Clean when it gets dirty again. That will depend on how often you play it, what type of rubber is in the game and how fast that deteriorates, how dirty it is now, and how well you clean it.

Don't use anything with silicone, it will cause fisheyes if the playfield is ever clearcoated. I couldn't find "Beeswax Furniture Cream" to check the MSDS.
Blitz wax is used to protect the surface after you clean it. https://www.pinballlife.com/blitz-carnauba-paste-wax-12-ounce-jar.html
Lots of good info in this cleaning guide (rip vid1900 )- https://pinside.com/pinball/forum/topic/cleaning-and-waxing-pinball-machines-vids-guide

Don't forget to inspect the balls. Replace them if they show any wear.

Generally in the $500 range. They are often sold unpopulated, you'll transfer all the pieces from your old one to the new one. If a reproduction one is available $850 or so is about what they go for.

If you're looking for one here is a thread for that: https://pinside.com/pinball/forum/topic/nos-playfields-you-havent-seen-and-i-havent-seen