To eliminate odors inside your shoe, simply fill a loose knit sock or some pantyhose with litter and tie it off. Work it into each shoe and allow to sit for 24 hours. The litter will help dry up the stinky bacteria that causes the smell, and it's likely a lot cheaper than powders and potions sold at big box stores (especially if you've already got it on hand). Via Trails.com
Thanks a lot there buddy. I tried this hack last night and this morning my old sneakers smelled so badly of cat urine that I had to double bag and toss them out. They would have smelled better if I had stuffed them with Elephant Dung.