[More Dust than Rust]

I'm not sure the oil companies and their high dollar marketing campaigns are going to like that evaluation (although I agree). Seems like they all have a magic oil blend, and pictures to prove, that their oil will make an old engine like new inside. There actually is some science to it and standardized tests to determine how much deposits are formed in an engine that has large amounts of blowby intentionally introduced (to Prof. Henry's point of suspension). The science of "sludge" removal seems to be a thing of internal company tests and before and after pictures.

Are any of us going to be putting that many miles on these engines between oil changes that it really matters? I bet out of love and boredom most of the guys here change their oil way more often than the original owners would have even thought of and they were running much less efficient lubricants.

Like others have said, drop the pan, clean it out, maybe throw a coat of paint on it, replace the gasket and refill with whatever you feel comfortable with. Whatever winds up going in is going to be a better lubricant than some of the stuff your engine has likely had in it before.