> On average credit cards have almost 2x the volume of germs as cash[1] They measured this by surface area, which makes zero sense in this context. You need to

> On average credit cards have almost 2x the volume of germs as cash[1] They measured this by surface area, which makes zero sense in this context. You need to measure by value spent. If I need to spend $200 over a week in multiple errands, how many germs for a card vs cash? The credit card is always the same germs while the notes are new germs every time they change hand and can spread nasty stuff much more easily.