I'm giving @viridian 's vinegar suggestion a go. I remember years ago when I had rental properties that a previous tenant's hallway had a strong urine odor. I read that treating the area with a solution of baking soda and then later treating the same area with a solution of vinegar neutralized the smell, and it worked. I also appreciate @mitch2 's same experience, maybe we purchased from the same seller. If vinegar doesn't fix it, I'll just hang them outside or in the garage and check on them occasionally.
Thanks for everyone's comments!