re: Homebrewing: In-Process Thread

Does anyone have any knowledge about deep cleaning a barrel? I am going to attempt to kill off everything in my barrel this weekend. The beer I have been working on for a while has turned to vinegar ( ) and it is time to get it out of the barrel and do some rescue on the barrel if possible. From what I have gathered online a sodium carbonate/percarbonate solution for a day followed by a citric acid solution, then 150 degree water is a decent place to start. I could certainly attempt to release sulfur into the barrel, but that seems dangerous. I am prepared to cut my losses if I cannot get it cleaned out, but obviously am going to try anything I can to fix it.