Cleaners that damage System 11 plastics and mylar
Do not clean these games with Wildcat-brand products or CP-100: they attack plastic, can turn ramps yellow and can make playfield mylar lift. A mild plastic polish (such as Novus #2) for the playfield and rubber, a metal polish (Novus #3) for metal parts and a carnauba or paste wax for the playfield are safe choices.
Systems
Source: Repairing Williams System 11 Pinball 1986 to 1990, Deel 1, Clay Harrell (pinrepair.com)