When dealing in cash, one can "skim" off the top. Let's say that a business makes $2000 in cash sales in one day. Now being that there is no written documentation in the form of credit card charges, or written checks, no one really knows exactly how much money was made that day except the person handling those cash sales. So that person can take $500 off the top of the $2000 made, put it in his pocket, and then legally record that he made $1500 in sales transactions that day, hence the term "skim."

Don Cardi