[Lylebobyle]

How does one blow off CO2 in a keg that has a solid lid or has had the check valve ring removed? Why would one remove them anyway? Can the post pin just be depressed to relieve gas?
I have a friend who bought 12 used Corny Kegs to use, but they are this way. Really don't want to have to buy all new lids with pull rings.....unless I have to.

[jeffy]

Most pin lock kegs do not have pressure releief tabs.  You simply depress the center post of the gas fitting to let off pressure.

[Stevie]

A special tool is made for the purpose as well. Not worth ordering on its own, but might be nice to add on or find it locally

http://www.homebrewing.org/Pin-Lock-Keg-Depressurizer_p_3187.html

Other shops sell it as well, but this was the first google result.

[klickitat jim]

Is it a normal keg but someone stole the wire ring? If so, put a piece of wire on it so you can pull up on it.

[reverseapachemaster]

On some pin lock kegs there is no check value on the lid. In that case, your only option is to use the gas post for this purpose. Other pin lock kegs have a metal stem that comes up with plastic inside as a check valve and you need a special tool to activate the valve.

If the lid has a regular check valve but the wire ring is missing then a piece of wire should be fine.

[stevedahl35]

Northern brewer has an add on pressure relief valve for $5 for the static pressure relief lids (coke style). Just drill a 3/4 inch hole on a flat spot on the lid, it seals with an oring and a nut. Better than buying a new lid for $20 or more.
http://www.northernbrewer.com/shop/keg-pressure-relief-valve-assembly-replaces-dome-style.html