Scruffy,
After your post, I know for sure I will never put my ABS tokens in my mouth, if ever I was inclined to do so in the first place.
Think about how dirty money is the next time you are at a fast food restaurant after the cashier hands you back your change and then proceeds to handle all your food as she packages it for you to go.
Yeah, we could argue how well our skin actually protects us, how much minute amounts of metal salt formations on tokens really figure into the equation, etc. The bottom line is: one should not do things to invite bacterial infection. And handwashing is always a good habit, as those OCD folks will tell you.