I have read a few topics relating to lagering in corny kegs after final gravity has been reached. My question is do I push a small amount of CO2 into the keg to seal the lid and then disconnect the CO2 supply or what?
That is what I did and it worked great. I put about 10 PSI in there and even after 30 days it had enough pressure to keep it sealed. I hit it with another 10 PSI after the first 30 days, left it for another month and then connected it to carb up.