I wouldn't lube the outer surface of the seal, just the inner lip where the crankshaft slides. Indeed, I think you want very clean metal against the rubber body. I have pushed rag thru w/ a stiff wire, after soaking the rag in ethanol.
I think you need a small drop of SuperGlue on each mating face of the seal so it doesn't leak thru the gap. It can also leak oil thru the metal gap around the seal. I think you are supposed to seal that w/ "anaerobic sealant", which I think is just high-temp SuperGlue. As I recall, the slant seal housing is aluminum so be real careful not to strip the threads. You might want to try to find a slant manual from the 80's. When the original 60's manuals were written, there might not have been more modern sealants available.
