Odor removal for leather?

I have tried many products to remove animal odors from my shoes and belts, but to no avail: some mint-based leather deodorizer, Febreeze applied with a cotton ball, various leather cleaning products, full strength orange oil, full strength Pine Sol, even full strength bleach. Within 48 hours the smell of the cleaning product fades away and the bad odor reappears even though these items are no longer kept where they picked up the odor. I'm ready to throw the items away but thought I'd check here. Any suggestions? Thank you.