Keg cleaning is the most thankless job assigned to rookie pros. Thankfully, Corny kegs pull apart and clean easier than commercial kegs. Most of the time, a keg can be cleaned and prepped for use in twenty to sixty minutes. If you've purchased unreconditioned kegs, follow the longer breakdown steps.
Typical Keg-Cleaning Steps
Rinse the keg immediately. Spray out the beer sludge. Close the keg up and pressurize if you're waiting for several kegs before cleaning. This uses cleaning supplies more efficiently.
Fill the keg with a hot cleaning solution. Use a carboy brush to clean the bottom. Hang the lid in the solution with the pressure relief valve cracked open. Wait ten minutes for a relatively clean keg, longer for a grungy one.
With the lid on and closed, push the cleaning solution from the first keg to a second rinsed, but dirty keg. Do this with a hose with black liquid fittings on either end, commonly called a jumper hose.
Spray out the keg with hot water until the interior is thoroughly rinsed. Place upside down and drip dry for a few minutes.
Fill the rinsed keg with sanitizer solution to the brim. Seal and wait several minutes. When done, push the sanitizer out to a clean keg or other holding vessel. Pressurize the sanitized keg and store until needed. Break kegs down completely at least yearly.
The “Complete” Breakdown
1a. Before filling the keg with cleaner, use a deep socket or crescent wrench to unscrew the posts, poppets, and tubes. Leave the long dip tube. Keep each post's parts together. Mix a strong solution of cleaner and soak the fittings. Proceed to Step 2 (above).
2a. Using a dip tube brush, scrub out the beer tube. Let the cleaner in the keg run up the line. Inspect and smell the rubber gaskets (five in all — keg lid, two outer post rings, and two dip tube rings). Replace any suspect rubber. Rinse off all the parts and reassemble onto the keg before proceeding to Step 3.