Wipe your feet!

Our neighbour's cat has started sleeping on our welcome mat every night and I'm afraid he also uses it as a litter box because when I open the door I can smell his urine. That's why I hid the mat behind the big flower pot at the door.
I guess that  the cat won't be able to sleep on the mat now, but all the same we won't be able to wipe our feet before entering the house.