ah, it could well be oak tanned. i noticed it stained my hands blue black just like when i work with freshly cut oak. the leather is also very stiff.
do you think liquid nikwax would help? it says on the lable that it is good for saddlery
pete
Oak bark tanned is quite a stiff leather at the best of times, soak in warm water for about ten minutes and flex whilst in the water, it will go very pliable almost like cloth in it's flexibility.
When it dries it will dry like rock.
Allow it to dry as slowly as it feels like, but do not expose to the heat from a radiator or other heat source as this will cause splitting along the bend line on the outside. The splitting looks almost like where you split layers of paper by placing pressure from inside to out.
I would suggest somewhere dry and preferably hung so that there is reasonable air flow around it (I use my shed).
I would then use oils and waxes on it afterwards.
I have never used liquid nikwax so cannot say, I can however say that saddle soap has been used for years just because it works and many people still use it over the new waxes.
On oak bark tanned you could use mink oil as well, I do and I know Roger Harrington uses it on his sheaths as well.