We may as well assume that the two pennies were equally dirty in the same way. Perhaps the pennies came from Doc’s cache of penny jars hidden in a closet. In any event, I reckon it is pointless to get picky. I’m no scientist. Sure, it is proper to determine the potency of the lawn chemical, but if you don’t have a proper lab (what vet would?), then this basic “Mr. Wizard” experiment will have to do for a start.
The real point is that the story is moving along with Doc and Cherry performing an analysis to discover if the lawn chemical might be the cause of the rash. Cleaning a penny quickly is not exactly proof of causation, but it’s a start. A gold star to Cherry for making the initial connection.
I wonder if Rivera is going to give Cherry a second week or jump us back to the more problematic Texas Tiger Zoo and Spa adventure with Mark “Call me Slim” Trail, Rex Scorpius, and Diana Daggers.