Where can I exchange 5K worth of Euro Coins in to Cash

[Gerry Canning]

Nice story;

Ring the Central Bank in Dame Street and ask will they take your coins including the copper.

 

[Drakon]

You'd probably get a 1:1 exchange from the Central Bank.
I can't remember the exact details (I've tried googling it), but a few years ago the Central Bank spent something like €3m to remove €30m worth of coins from circulation. Due to the recession and lack of spending, there was excess amounts of shrapnel in circulation. The removal came at a cost.
Pity it is in €1 coins. If it was 1c or 5c you could try melting it down thereby increasing its value. (...Joke...)