How do you get rid of co2 if you over carb a keg?

Do you need to shake it and purge, or do you just bleed it periodically over time?

Bleed and wait... Bleed and wait...

(To be sung to the tune of Edelweiss)

Shaking may cause more CO2 to disolve into the solution making your problem worse.

Depends on two things:

1) How overcarb'd it is.
2) How soon you need it drinkable.

A "tame method for knocking out CO2 is to loosen the lid and set it ajar for 12 hours at a time...testing it along the way. If the keg is cold, it will take much longer for the CO2 to escape solution.

A more aggressive manner, one which I've used, is to remove the lid, stick in a sanitized paddle and give it a very gentle stir until you see foaming. Think of it like stirring a glass of beer.

If the keg is severely overcarb'd, be very careful with this method. Removing all of your kegs from the kegerator and mopping up 2 gallons of foamed over beer is no fun.

trust me.

If you leave it off the gas, as you pull off a few pints the headspace pressure will drop and eventually it will calm down.

I just leave the relief valve open for a day, then set it at serving pressure and let it recarbonate over a weeks time, that way it won't overshoot.

Let is warm up some to speed the release of CO2. Kept cold it will take longer than you might expect. Pull the pressure relief valve anytime you are near it. Sample it occasionally and when it's about where you want it, chill it down and put the gas to it at serving pressure.