When I bought my Brooks B17 I turned it upside down (having detached it from the bike it came with) and coated it with proofhide. Then I put it in front of an open fire (coal not wood). When the proofhide soaked in I put another lot on, carrying on till I got bored with it all - or maybe I ran out of coal.
The saddle really wasn't a lot softer but I could leave it out in all weathers. I always did my cycling in black shorts or trousers after that due to the marks it left on clothing for about a decade. After a decade it had become the most comfortable saddle you could possibly want and I got a further 9 years out of it (before someone nicked the bike). Even then, from not too far away it still looked good as new. Its successor (bought in a junk shop in Hawes for £3 in the 90's) is maturing nicely.