I used almost a full can of WD40 flushing out the lower chamber cylinder. I also used a small chisel and stainless wire brush on the caked up areas. Then wiped clean several times. NOTE: There is a pencil sized hole at the very bottom, which appears to be a contaminate trap. I used Qtips to clean that out. I also used AntiSeize on the threads "only" . This should mitigate any corrosion issues to the threads. I also recommend using a light coat of petroleum jelly for the outside ORing, before replacing the outer cover. Be sure the clean inside the lower plug, so you can clearly see the fill window. FYI: It does not take much oil to fill this unit up. The manufacture suggest half way to three quarters full, approx 80 ml. I have had this unit since 2017 and it has performed like a champ. This appliance has saved me thousands of dollars in food cost. Subscribe to this channel and the facebook page "Southern Home Talk" To keep up with all the other home preservation topics. Knowledge Is Savings. By: South Alabama Home Inspections 2514909892