Quoted from pinheadpierre:

What are you trying to achieve? Naphtha is great for stripping wax without stripping old clearcoat or paint. Alcohol is fairly aggressive in terms of dissolving many paints, inks and clearcoats. Novus 2 and magic eraser each do a good job of removing ground in grit because they are abrasive, especially magic eraser which is roughly equivalent to something in the neighborhood of 1200 grit sandpaper if I remember correctly.
If you’re not planning on restoring and clearcoating the playfield, stay away from alcohol and magic eraser. Basic cleaning is easily done by vaccuuming, light use of Novus 2 in heavily soiled areas followed by carnuba paste wax. Stick with Blitz or something similar with a high carnuba content and ZERO silicone content for waxing.

Quoted from pincity:

Just be careful if you’re not planning to clearcoat, as my understanding is that alcohol will dissolve the lacquer coating that’s on older playfields.

Quoted from pinheadpierre:

What happened is that the alcohol dissolved the old lacquer clearcoat. The sacrificial white melamine (magic eraser) got mixed with the dissolved lacquer. You didn’t remove 100% of the lacquer so it partially reset. You were able to grind it out with the lesser grit of the Novus 2. Again, if you’re not going to reclear an old game STAY AWAY FROM ALCOHOL. Trust me on this. You’ll regret it in a few years. Don’t ask me how I know....

Quoted from pinheadpierre:

Let’s see a picture.

Quoted from pinheadpierre:

I’m sorry but you can’t clean that out. What you’re looking at is old lacquer and ink which has cracked all the way to the wood due to years of expansion and contraction. The dirt is on the wood in the cracks. If you scrubbed it enough to make a difference, you would absolutely need to reclear it and even then it wouldn’t be totally gone. My recommendation is a light cleaning with Novus 2 for surface grime. Then wax it and enjoy it. Maybe someday you’ll be ambitious to undertake a repaint, but until then forget about trying to clean that away!

Quoted from pinheadpierre:

I’m sorry but you can’t clean that out. What you’re looking at is old lacquer and ink which has cracked all the way to the wood due to years of expansion and contraction. The dirt is on the wood in the cracks. If you scrubbed it enough to make a difference, you would absolutely need to reclear it and even then it wouldn’t be totally gone. My recommendation is a light cleaning with Novus 2 for surface grime. Then wax it and enjoy it. Maybe someday you’ll be ambitious to undertake a repaint, but until then forget about trying to clean that away!