their poop is why I don't let them in the house, so kudos to you for dealing with it 
the nearest I get to your problem is poop on the quarry tiles round the back door (where they hang out when it's wet, which is often in winter, and when they're hungry), where a stiff brush gets rid of dry stuff and a wet brush gets rid of cecal.

the nearest I get to your problem is poop on the quarry tiles round the back door (where they hang out when it's wet, which is often in winter, and when they're hungry), where a stiff brush gets rid of dry stuff and a wet brush gets rid of cecal.