You can't be serious.
So how do you ensure that you are not passing off fake notes to others?
Is this a business transaction that occurs normally in your business?
Are you a registered money exchanger?
Are you insured?
Registered as a business?
Are you legaly entitled to conduct business here?
Honestly I dont know how many of these questions apply to you. But you may want to look into it if you want to exchange money with people you dont know.