I can attest to the RJS and the nasty sh*t they get everywhere under the undercarriage. My 87 442 had it done in Ohio right after the car was purchased new by the original owner. What's worse, my 85 got a similar rust proofing thing done AUTOMATICALLY when it got to the dealership. I didn't pay for it because they wanted to add it on and I told them I never authorized that stuff. Scrape it off for all I care.
I just spent 12 hours of my life scraping that lanolin oil like crap off the back half of my Monte. I cannot bear to look at the car right now... it hurt me deeply.