Answered by Shaykh Faraz Rabbani
I recently adopted two kittens and even though they use their litter boxes (Alhamdulillah) they may step in their own filth and continue to walk around the floor. My questions is, does that make any place they step no longer clean for prayer? Also if I step on that spot and continue to the rest of the house, do my steps make those spots impure? Is there any purification process I can do to my hardwood floors?

Assalamu alaikum wa rahmatullah,
One assumes purity until it is certainly established that something is filthy–by clear traces of the filth. As such, the walking around of the kittens will not be considered to affect the ritual purity of our floor and furniture.
Please see the following related SunniPath Answer:
How come cats aren�t filthy?
What is the ruling of cat saliva? Is it filthy (najis)?
Jazakum Allahu Khayr
Wassalam