I put some time in on a dirty, cracked, rodent-chewed, flaring, unidentified leather saddle off a 60's Peugeot recently. This is what I did:

1. Soaked it in water a couple of days. This was to rehydrate the leather and soften up the caked-on grime on the top of the saddle. After soaking I wrapped a bunch of zip ties around it to help fight all the flaring that was going on.
2. Cleaned it. I used wet cloths and Lexol leather cleaner 'cause that's what I have on hand for my shoes. I kept cleaning until I couldn't really rub any more grime off, but wasn't rubbing away the leather.
3. Conditioned with Lexol leather cleaner 'cause that's what I yadda yadda...I applied a number of times as the leather really soaked it up.

Then I rode it a while. The flaring returned so I tied it with a leather boot lace. It's been improving, but I still get some brown marks on light pants so I'm thinking of applying some Sno-Seal to try to give it a "sealed" surface kinda like a new Brooks.