Sell the euros at a currency exchange office. These are often in malls and banks, and in their own retail store locations. Some currency exchange businesses allow you to mail the currency to them. Note that they might not accept coins, however.
Exchange the cash through your own bank. Procedures may vary from bank to bank, but in general, you must bring the euros to the bank and exchange them at a teller's window. It is possible that the bank might not give you dollars at that point, instead depositing the corresponding U.S. dollar amount into your bank account within a couple of days.
Call hotels in the area about their currency exchange services. Higher-end hotels often provide currency exchange services for guests; check and see if they'll buy your euros even if you are not a guest.
Exchange the euros at an airport. International airports such as Los Angeles International (LAX) have currency exchange offices and kiosks within their terminals.
