Don't use oil, true, but there is (or was?) a product called "Fast Fret" which put a light coat of lube on the strings and made getting around the fingerboard a lot easier, particularly if you are into slides. When the lube in the applicator gave out, you could refresh it with a shot of WD-40. I always liked the results, as long as you do not overdo it.
Any other comments?
MarkS