Neither of the things you’ve described make money dirty. Just because a dollar bill comes into contact with cocaine (often in cash sorting machines in banks), it doesn’t mean that it is the proceeds of crime.
I think his point is that a sizable portion of physical cash is involved with crime, that's one of the benefits of using cash so it only stands to reason- Yet everybody still uses cash regardless. Though I'm sure this same argument will be used in the future to justify a transition to a cashless society where all transactions are traced