If your kids are like mine, they come in from playing outside and their hands are filthy! I don’t mind them getting dirty, but I do mind dirty hand prints on my walls and furniture. My kids do a pretty good job of washing their hands but they don’t do a great job of getting all the dirt out from under their fingernails.
I keep a cheap scrub brush next to the sink so the kids can scrub their little fingers when they come inside. This scrubber works great for adults too. When we had our garden I would use the scrubber to get all the dirt off my hands and fingernails as well. I think they cost less than a dollar and they last forever.