Odor eater for shoes.
Oh. Sorry, don’t know about the kitty litter.
I’d put baking soda in them or saturate them with Lysol spray.
If the sole liners are removable, take them out & wash them with dandruff shampoo because it has an antifungal in it.
Use for boots, shoes, dresser drawers.
Why would you put kitty litter in a sock?
Renee: even less messy than kitty litter is just add some charcoal to a sock and push inside! (NOT charcoal soaked with lighter fluid!)
...I do this to our winter, ski, and hiking boots. Works great!