The one thing that's worked well for me are cotton balls soaked in
Lysol. I keep a tupperware of them in my grooming tote and use my hoof
pick to press them in the hoof. They either fall out or are removed
next hoof cleaning. It kills bacteria, but it's not so toxic that I
have to worry about getting it on mine or my horses' skin.
Melissa, Callie & Lil'Bit
Las Vegas, NV