Sorry to say it, but goof off is a plastic destroyer. I hope you can polish it out. Not sure if the flame will work. That is more for scratches and scuffs. We used to buy games at auction games sales in Ohio and indy. They used a really nasty sticker for bidder numbers. I ruined so many headers trying to get that glue off of them.
Quoted from CrazyLevi:Goo gone, NOT goof off for tape residue.
People been mixing this up forever always with disastrous results. You are lucky none of that stuff dripped on to the playfield.
I have used goof off on a playfield. A few times on wms dmd games. Sometimes you get desperate and do desperate things. Never ruined one.