My children were told to always pick up whatever they got out to play with and they did that most of the time but now the grandchildren are a different story. They are always making a mess and leaving it. I told my husband I was going to quit letting them have anything. One grandson lived with us a few weeks and he didn't leave anything out I could see. When he left I was giving my living room a good cleaning and found 7 sandwiches in my end table drawer. They were molded. He had moved several miles away by then so I called him and asked about them. He said they were an experiment. Now I always check everything when they leave.