Remember when you were a kid and spotted something on the ground that looked appealing? Did your mom say, "Don't touch it! you don't know where it's been."

It might be a good idea to apply that kind of thinking to money. You literally don't know where it's been. Scientific American says handling cash is one of the world's most effective means of spreading disease.

Paper money is often tainted with mold, multiple strains of bacteria, cocaine, heroin, even fecal material! American bills are the world's worst, especially small denominations. They're made of cotton and linen.

Other countries, such as Canada have actually introduced bills made of plastic. No wonder cash is also known as "filthy lucre."

Modern technology has enabled us to drastically reduce our use of cash, between debit cards and features like Apple Pay.

I rarely handle cash anymore. I wash my hands a lot, especially after handling cash. I also get plenty of sleep.