Important to remember:
Teach your children NOT to pick up coins that they find on the floor of public bathrooms. Otherwise, you'll find yourself watching your seven-year-old crawling on her hands and knees on said public bathroom floor to collect said coins. And you'll be so stunned and horrified that you will be incapable of speech and therefore not able to tell her to get up.
But, you will have the presence of mind to scrub her hands and the money thoroughly AND give her a hot, sudsy shower later on.