Here's a PSA for you: ALWAYS wash your hands after handling money.
Liam was streaking around the house a couple of weeks ago in a pair of briefs (I believe that I had been trying to get him to take a nap. That's not important, now). I was in the bathroom putting on some makeup, or brushing my hair, or something equally unimportant when he exclaimed in triumph that he'd "found a money!!!" He wanted to know if he could keep the penny he'd found on the floor and I, naturally, said sure, good for you, kid.
Went back to whatever I was doing... Liam went back to not napping.
A few moments later, he toddled into the bathroom, oddly empty-handed (Liam usually holds onto his pennies tighter than Scrooge himself). I asked, with a bit of trepidation, what he'd done with it.
"It's in my pocket, Mama!"
Did I mention earlier that he only had on his underwear? Yup, you got it. He had put it in the pocket in his briefs. And he was just so proud of himself...
So, yeah, you really don't know where that money's been.