Having had to do it many times, I ought to know:)
Of all the jobs I've had to do as a mother, that is the one that grossed me out the most. Some #%@#% would let their dog roam and use our lawn to do its duty and one of us would invariably step in it. And we don't even own a dog. It would always happen to a pair of sneakers that we couldn't afford to just throw out; like new ones with LOTS of tread. ARGH!