Quoted from pinheadpierre:
I am not a chemist and can’t offer an explanation as to the why. All I can tell you is what other experienced pinheads have reported coupled with personal experience. For a relatively slow moving em, you might get away with stripping off the clear (likely lacquer) for awhile if you’re REALLY meticulous about cleaning and waxing regularly, but eventually it may catch up with you.
Case in point: I took the alcohol approach with my first pin years ago before I knew what I know now. I cleaned a really dirty Space Shuttle with 91% isopropyl alcohol. It cleaned up really well, but also dulled it slightly. I was meticulous over the years about regular cleaning, waxing and using only new balls which I would change fairly frequently. For the most part, the playfield survived in its post-cleaning condition with the notable exception of high repetition ball travel areas. After roughly 4 years of home use, the paint in the pop bumper area, rollover lane exits and targets had worn to wood. Similar games which I have cleaned only with naphtha have not suffered this type of accelerated wear.
I do think that so long as nobody has stripped the original clear that you have to be careful about choosing between cleanliness that is prone to potentially accelerated wear or a dirtier looking playfield that will survive longer due to the additional sacrificial layer of dirty, thin, aged clear.
What php says here is very true...I'm silently shocked at the number of folks who seem to advocate using methods that clearly remove whatever CC remains, then don't replace the clearcoat with anything other than wax. But PHP's story is the first I've heard of someone only waxing and then experiencing accelerated wear afterword, so it's kind of vindication in a way.
I don't advocate following Vid's guides to the letter, read what other do and consider those options too, or a blend of all techniques that suits you. But there is a ton of great info in those guides presented very well...and specifically a great visual explanation of why alcohol and magic-erasers work so well at "cleaning" the PF - you are removing no only the surface dirt, but dirt that's embedded in micro cracks in the original CC by removing that old topcoat altogether. It's like, almost science man!! lol
You don't HAVE to use 2PAC auto-clear to CC your PF after removing the old topcoat...but you do need to protect it with something. I use Acrylic Lacquer in spray cans from Krylon...sure, it will probably yellow again someday, but all my games are old EMs with a patina that matches anyways. Other folks use equivalent products for various personal reasons, but most of those are less dangerous and more forgiving than the auto-clear, and to me, that's what binds these solutions together. I know you can get the 2PACs of the world to appear more like the original with the correct application, but this is a learning curve I personally don't feel I need...I'm happy with the results I'm already getting with my tried and true methods.