Find some information on cleaning pigskin. It used to be much used for fine gloves, for jackets, soft bags and the like, and those got really grubby on edges, cuffs, etc.,. If I mind correctly we used talc and rubbed it in then brushed it gently out, for stains we used bicarbonate of soda. Again, rub it in and then gently brush it out, hopefully with the contaminants/dirt and oil that stained it. Should work with smokey smells too. Not expensive to use either, unlike the foam sprays that the cobblers sell for suede shoes and boots.
If you can get to a poundstore, they sell packs of 'magic erasers', white blocks of foam type stuff meant to take marks off painted walls.....those work on some stuff like bags and shoes too, so might do ?
I think I'd try the bicarb. soda though.....maybe on a scrap first since you made it yourself and probably have bits ?
M