I prefer to just put a slice of fresh prime rib in the bag. But, I have expensive tastes, ha ha.
Lots of people put oranges, apples, and bread obviously. It seems to work for them. But, I just either leave mine in the tin or the jar till I want some, and then leave them out to dry to whatever consistency I like.
I've tried the leather pouches, but after setting on my tobacco all day, it just turns to dust.