What banks will change dollars into pesos without requiring you to have an account with them?

#11
Banco Piano, Microcentro, Caballito, and Flores will exchange dollars for pesos with no hassle. HOWEVER, the green must be pristine! Not a mark, no a blemish, not stampings, nada. Pure as if it just left the mint, or they will discount the bill(s) in question 20%! (I have found many banks do the same)