I had a cat that peed in my shoes until he was fixed. You'd think the smell was washed out, till they warmed up or got wet.
LOL I had to throw away some fly sheets. The cats got locked in my tack room one night and needed a place to whiz. They chose my stack of fly sheets. I washed them, bleached them, everything you could think of and thought I had the smell out, until of course a warm horse wore it. I tossed them in the trash.