I recently was volunteering at a horse event. After 30 days of no rain and bright sunshine, the day I volunteered the heavens opened and it poured. Not surprising.
I was wearing light, comfortable, fabric, sneaker-like pullons and no socks - as it had been California-dry for over a month. I finished my duties for the day and into the night in absolutely sopping wet shoes and by the time I got home many hours later, my feet were so pruney they hurt.
I left the shoes in the laundry room to dry out, but by the 3rd day they stunk to high holy heaven.
I washed them with laundry detergent. I left them in the sun for a week. I sprayed them with a strong bleach solution. I soaked them overnight in chlorhexadine. Nothing worked.
Thinking I was going to have throw the shoes out, I read somewhere about trying OxyClean. I made a paste with the stuff, rubbed it in good into the fabric and soles, let it sit for a couple of hours, then immersed them in a bucket of water and agitated them until the water became foamy. Then let them sit for another few hours.
Then rinsed them until the water ran clear, filled them with newspaper to dry. Changed the newspaper every few hours, and voila!!! no more stink!
I’m amazed OxyClean worked better than chlorine bleach.
I agree, if your barn has a strong odor, you need shoes dedicated for the barn. But if you’re desperate to try to salvage these, maybe OxyClean will work for you.