I bought scigrip 3 and industrial syringes. If you come across this thread, do not waste your money if your game is an old chicago coin.
I tried it on a plastic for a 1975 Olympics. It did nothing.
It did not soften old plastic at all. It dried too quickly to fasten plastics. And is too thin (viscocity) To work without submerging plastic in it. At that point you risk loosing the screen printing.
I do not know if it will work on modern plastics but i will not be trying that. It is headed for the trash.

That is why i was specific about the game and the age.
It looks like it worked great on your plastic.

#Zitt
I had that same feeling. Perhaps CC used a different plastic than other manufacturers.
I also thought it just may be too old and whatever the scigrip reacts with has long left that old plastic.