exchanging WW money for Muggle money

[meltowne]

No: HPFGUIDX 77698

Of course, the goblins or anyone else from Grigott's may not ever 
even have to come in contact with Muggles.  When Mrs. Weasley sent 
the letter with all the stamps on it through the Muggle Post, she had 
to buy the stamps.  Where did she get the money to buy those stamps?  
By exchanging for it at Gringotts.  Muggle-born students put the 
muggle money into the system when they need to purchase supplies; 
other wizards take it back out when they need to purchase something 
in the Muggle world - no different than our own exchange system.  The 
bank employee who exchanges your US Dollars for Yen or Lira (or any 
other money) doesn't need to know anything about the language or 
cluture of that country.  They just need to know the exchange rate.

Melinda