I've been researching threads here about conditioners and darkening. Most conditioners, it seems, will darken temporarily, as I would have expected. And I've seen one or two mentioned that do not darken. Well, I'm looking at an old jacket on eBay. And if I get it, I'd like to bring some "life" back into the leather and darken it. What conditioner do you recommend for "permanent" or "long term" darkening? Oh, it's front quarter horsehide. Here's a photo... Spasibo.