Someone may have some idea.....
Having stripped my playfield, (f-14 Tomcat Williams) I gave it a good old clean, and used ME and IA to get the extra dirt ball swirl etc, came up quite well very happy with the result.
Somewhere along the line I decided to pop the inserts out of the playfield, as the decals, they were decals, had deteriorated somewhat.
Got the inserts out OK, but where I had heated them gently with the hairdryer, the topside of the playfield went a little dull.
Went to clean around the inserts with ME Foam and found the surface had changed and I was now getting something on the eraser.
As MartyJ replied earlier, (thanks mate), the fact that the inserts were decalled would mean that they had been repaired before.
Here is my theory, I believe this playfield has been restored before, perhaps with a Varathane clear over it (or similar) because now the crap turning up on the foam is yellow. I am also starting to think that the whole playfield has a slightly yellow tinge to it. I think I read somewhere that Varathane will come off with the application of heat. What does anyone think? Am I on the right track or am I totally mistaken?
I am now thinking of polishing with novus (seems to clean up the mess) and going lightly over with ME again to see what happens. Anyone with any ideas I am open to anything that may help, I have put too much time into this to just give up now.
Cheers,
Lindsay