My wife leaves tooth brushes in the shower and brushes her and the children's teeth in there. It's a huge waste of money first of all, but I've tried to explain how disgusting it is too. We stand in there and wash our dirty bodies off. That dirt flies all over to include on the tooth brushes. That's pretty gross to think about, right? Yuck!

Your experiment reminds me of the devices used to detect blood splatter. I knew a police officer once that was a blood splatter expert. I've studied to become a residential security expert and private investigator instead, but he had spent his entire life studying blood splatter.

He helped teach one of the digital forensics courses I took in the past at George Washington University.

Then theres' the microbiology class I took in college while I was still considering medical school to think about. Bacteria is all over the place. If you realized how bad it was, you'd spend half your day scrubbing everything near you and your body. I make sure my immune system is very strong because of that knowledge as well.