Cleaning your kegs is easy. When your used kegs arrive, they will probably have soda residue or concentrate still inside. Drain and scrub the inside of the tank, don't worry about scratching it. Add a gallon of hot water (100-160°F or 38-71°C) with 2 oz of PBW Powdered Brewer's Wash or equivalent cleaner (see label for amounts and procedures). PBW is an environmentally friendly, biodegradeable alkali wash that will not harm your septic system, rubber gaskets, soft metals, or your skin. PBW can effectively clean items that can't be reached with a brush or sponge, and is strong enough to remove thick, difficult, caked-on organic soils. Seal the keg and shake vigorously. Allow the keg to set for at least an hour, but preferably overnight. Then drain and rinse the keg. Repeat the process, this time turn the keg upside down to clean all the top parts including the gas in line. Drain again and save some of the cleaning solution.
Using a 7/8" ratcheting wrench or box end wrench, disconnect the keg posts from the top of the keg (it may require a different size wrench for various manufacturers of keg posts). Push out the poppet valves and drop these into the hot cleaning solution to soak (I try to keep the poppets and keg posts together). Use an old toothbrush to scrub the inside and outside of the plugs and poppet valves. Pull the gas and beer tubes out of the keg and scrub with hot cleaner. They make special brushes to clean the inside of the long beer tube.
Remove and replace the o-rings on plugs and tubes (if needed). Clean the keg lid and replace the large o-ring as well. Rinse everything in hot water several times then put it all back together adding a little silicone to the o-rings. Pay attention to where the tubes and keg posts go, the short tube always goes below the "IN" post, which should have notches on the base.
After the keg is clean, pour a gallon of clean water into the keg and add a no-rinse sanitizer such as StarSan. Shake the sanitizer around making sure to cover the entire inside surface. Wait for 3-5 minutes for the sanitizer to work. Place the gas quick connect from the CO2 regulator onto the gas "IN" side of the keg. Place a picnic tap with quick connect onto the "OUT" post. Turn on the CO2 to about 5 psi, open the picnic tap and dispense the sanitizer into a bucket or another keg. I usually run it for 20-30 seconds to sanitize the inside of the beer tube and post.
The outside of the used kegs will be dirty, dented and sometimes full of stickers. Clean them as necessary. After cleaning your kegs, try numbering the kegs and keeping a log of when the o-rings were changed, when the keg was cleaned and sanitized, etc. It's easy to forget how long the o-rings have been in service otherwise. The kegs are now ready to be filled with beer. Some homebrewers store them with sanitizer inside and under pressure to keep the lid sealed tightly.
Keg and beer-line cleaning kits are nice, but I feel they are unnecessary. I add a gallon of hot cleaning solution (One-Step or PBW) to the keg and hook up the beer lines from the tower or taps. Connect the CO2 quick connect then run the cleaning solution through the beer lines on your kegerator as if you were serving beer. I then dump the cleaner, add sanitizer to the keg and run the sanitizer through the lines (Skip this step if using One-Step as your cleaner). Hook CO2 to the gas "IN" side of the keg. Place a picnic tap with quick connect onto the "OUT" post. Turn on the CO2 to about 5 psi, open the picnic tap and dispense the sanitizer into a bucket or another keg. I usually run it for 20-30 seconds to sanitize the inside of the beer line tubing and posts.
Cleaning your kegs shouldn't be such a chore. After you do it a few times you will get the process down and have any jumper lines made up if needed. One very important thing to remember is to heat up the PBW, it works much better.
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