I am selling my older Stubben that has been sitting in my bedroom for 6 months, however before I bring it to my local tack shop it's going to need some serious TLC. It's a Seigfried (I think I spelled that correctly?) and has suede knee rolls. The leather has gotten stiff and slippery, and I need to start getting into a regular cleaning routine before it is sold. I don't ride in it, I just need some input on what you guys use to get old stiff saddles soft and ready to sell. Also the suede has black marks from tall boots i'm guessing and I am not exactly sure how to cleanse the suede and get the knee rolls looking new.
You could try a suede brush on the knee rolls but I don't think I would bother too much about that, you might do more harm than good. And Stubben Siegfrieds tend to be slippery at the best of times IMO. I like the Effax products for cleaning, or Belvoir's liquid cleaner, also Tattersalls which seems to have a conditioning effect as well.
For conditioning seriously dehydrated leather I like any brand of Lederbalsam, or CWD cream conditioner, which is excellent. Akene is another good conditioner. I think most any cleaning and conditioning products will do the job, the important part is doing it with some regularity to get it back in shape. And I always like to finish with a polishing of glycerine, Epona being my favorite.
For dry, dry, dry leather, you cannot do better than mink oil, which can be bought from your local boot shop. It really softens and conditions the leather. As a bonus, it also protects against mold/water. However, if your saddle is very light colored, you might test a patch under the flap as it can darken the leather. This is never a problem for me because all my tack is dark brown/mahogany, but if you have a honey colored saddle, you might not like it.
I used the mink oil to revive a very dry collegiate from my childhood that I thought had been stored in a closet and instead was moved into the rafters of a garage a few years before I rescued it, cleaned it up and sold it. The before and after pics are remarkable.
I'd use use the stubben glycerin soap first, then follow with the mink oil. The Stubben Hamminol also is very good if you can't use the mink oil due to leather darkening issues.
Can't help on the suede patches as I've never had to deal with that.
1.) Belvoir Glycerin saddle soap (has added coconut oil). Skip this step if the saddle is dust free or already clean.
If you don't mind the leather being darkened:
2.) Neatsfoot or mink oil (1-2 applications, letting dry in between) If you don't want it to darken:
2.) Lexol leather conditioner (1-3 applications, letting dry in between)
3.) Leather balsam (I like Passier)
-Apply a thick coat--let sit overnight
4.) Wipe off excess, or clean again with Belvoir glycerin soap if wiping off still leaves a residue.
I have rescued a dry, cracked (stored away) saddle this way back to amazing/new condition that lasted. I used Neatsfoot oil for step 2 because the saddle was older and had already been darkened so it wasn't an issue.
Hope this helps and best of luck! Unfortunately I don't have experience with suede knee-pads, so I'm not sure what to do there.