>From Sheldon Browns' article on "Breaking in a leather saddle" (www.sheldonbrown.com/leather.html):
"There are probably lots of other liquid oils that would work as well-RAAM pioneer Lon Haldeman uses SAE 30 motor oil, but his saddles tend to wear out after only 300,000 miles or so (according to Cyclist Magazine)."
I have personally used this technique (10W 30 Motor Oil) a number of times on old Brooks saddles that I could afford to do without if they disintegrated (none ever did).
I am still riding on some of them years later (none with 30k miles on them yet!)
Two words of caution if you decide to try this on a saddle: 1. use motor oil with no chemical additives 2. don't ever wear anything but black shorts when riding the saddle, as you will forever get a nice print on your butt whenever you ride it.
Sheldon, we miss you!
Duncan Granger
Mountville, PA