If my neighbours cat pooed all round my lawn then ive scooped up most lumps but theres soft bits left will thi?

ever wash away? Its been out there now for months, but i have a toddler who wants to play out on the lawn and im worried she will get sick from this. Ive tried to clear as much as poss but theres still soft runny poo left in the soil around where the lumps were. Thanks