My niece wanted to play my piano, and I asked her to wash her hands. She said, "I don't need that, I have Magic Soap," and she produced a bottle of hand sanitizer.
Um, the purpose of washing your hands isn't so the piano doesn't get sick.
My piano-instructor cousin-in-law tells me that her young students often say, "My hands are not dirty. They are just a little sticky because I just ate a chocolate muffin on my way here. I don't think I need to wash my hands. Why do you always ask me to wash my hands before the piano lesson?"