I am aware that Jeremy at Maple Hill (great guy that does Virginia Mustang - Brant's cars) uses a product to seal and coat these interior surfaces or at least has done so on some of the restorations as shown in one or two of Brant's blogs on his site.
I saw that, and that is what got me thinking along these lines.
Not sure if Eastwood's product is a paint based or wax based (read Zebar) product. Luckily for people like me that live in the rust free zones I don't see the hidden surfaces to be an issue for another 50-75 years on our cars
Maybe some truth on your climate Jeff, but my car only spent 1/2 of one summer and a fall in Ohio outside as a driver, never saw the snow or salt and was indoors afterwards for 16 years. Prior to that it spent the first 30 years in arid Barstow and Palm Springs area. Only saw rain of So. Calif and car washes for those years. MICE seem to have helped add to whatever started naturally on it's own untreated cowl areas. Then there is some areas along the lower dash where the little fellas ran around that has some corrosion to clean off. I'm sure 16 years of humidity helped too.
addressing the products content,
cut/pasted from this page:
http://www.eastwood.com/internal-frame-coating-w-spray-nozzle.htmlTough phenolic resin penetrates, converts and encapsulates the rust on the internal surface
Zinc phosphate seals it to prevent future corrosion
24"-long tube with conical nozzle reaches in to spray coating in a radial pattern for complete coverage
Covers 10 sq. ft. per can
Fully cures in 24 hours
Cans retail at $20 each, I'd say after reading some reviews, probably 3-4 cans could do a whole Mustang.
Richard