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Wednesday 24 January 2018 at 00:57
Quoted from Sprudeldudel:It's not a wet spot. It's perfectly normal. The protector is so smooth that it will "suck" to the playfield in certain places. The air gap in between the playfield and the protector disappears and that looks like a wet spot. You can rub all you want. It will stay. Haven't se...
Source: http://pinside.com/pinball/forum/topic/pf-protectors#post-4191937