Wow, what a bunch of old hens! The guy asks for help cleaning and you idiots turn it into a debate about cleaning products LIKE EVERY OTHER CLEANING TOPIC!!!! Try answering the guys question instead of running off at the mouth every time something is posted.
To answer the question (hey, original concept)........
To clean the PF and just the PF (the actual wood/dp/cc/varnish) you should use whatever cleaning product your comfortable with (simple green/purple power/windex). What everyone usually agrees on is NEVER have any liquid sitting in the PF. Always spray onto the cloth and wipe down. If this doesn't get it clean enough, I usually use a little novus 2 and a ton of elbow grease. Try and use it sparingly as it is an abrasive. Some people then use novus 1 for cleanup of any residual. Then wax the whole thing with a good carnauba auto wax.
Cleaning everything else is subjective. Plastic ramps = scrubbing bubbles, metal ramps = never dull, PF plastics = warm soapy water with Dawn. Usually all of this is done off the playfield if your doing a deep cleaning. If your trying to clean in place, use a towel to keep solvents and liquid off the PF surface itself.
From what your describing, I would say it's time for a deep cleaning and that mean stripping as much off the PF as your comfortable with and doing a deep clean. Just go slow and take lots of pictures and you will be fine.