Bozuk para: Change

It's a genuine phenomenon... Turkish cashiers loathe to handle large bills. Fine, you say, just use acceptable demoninations. Ah, yes, but ATM's almost always dispense in 50s. Today I went to one of the major banks in Taksim Square to get bozuk para. I took a number, waited patiently for 20 minutes, explained myself in Turkish, and the clerk told me she didn't have enough small bills! (In the bank?!?) Guess I need to get more strategic...