The most effective way that I have seen was to announce in the flyer for the race, and in the supps that VC were going to be taken off and cams checked. And to bring the tools/people and parts to do this on SAT afternoon.
The valve covers did not come off ,but some of the cars slowed down.
Maybe put a short article in the CFR paper with your concerns, would be a smart start.
Throwing paper pisses people off. Having mam to man talks with maybe 1 beer( not 4) might be more tolerated . Most of these guys are pretty nice. but as the rules get let go , "everyone is doing it" comes into play.

FWIW I dont see a legal Toy running with a legal Mk 3 VW.
I have worked with both .
Be careful ,The 5-6 ITB cars that race in CFR might not race at all and then what do you have besides one trophy.

RE concerning visible issues like wiper blades. Some guys really dont know the rules. Tell them to put the wiper back on please.
How about the new Dodge 024 that had all of the car gutted etc. I talked to him for a few minutes, asked about the car, as it was really pretty just not legal. I mentioned that I ran Prod and did not know the current rules for IT, so I sicked Chip on the guy and he took his car and stayed home(I was pretty sure thatChip is more politically nicer than I) . The car was more of a Prod car . But pretty sure that we still lost him .
MM