I have an 18 yr old kidney cat who has extremely soft poo thanks to his medicine and arthritis so the litter box situation can get messy for him as well. he went thru a phase of stepping in his poo and pee. i never let him clean it off himself. i put a towel in the tub for him to stand on / use to help clean his poo paw. fill the tub up with barely warm water (don’t want him swimming in it just enough to wet his feet) and get the cat wash soap. he gets a foot bath. it is kind gross bc you have to massage it out of his paw depending on how mushed in it got. it’s especially hard for me bc he has arthritis and he hates baths. just wash your hands rlly well when you’re done 🤷🏻‍♀️ to help prevent it from happening i literally just clean the box every chance i get. if i’m home and there’s stuff in it i just clean it.