When I first got mine the previous owner had been using it for a huge Kalk system. It had stuff caked on all over. I filled it with water from the garden hose, added 2 gallons of vinegar and left it with a pump running to circulate for 24 hours. Drained and rinsed - perfect.Hi everyone! I have a large 50 gallon baffel like Don showed below. I have had it for over 5 months and I really need to clean this thing . What are some of your methods of cleaning out these really large containers when the entry is so dang small. I will post a picture of my setup shortly but I only have one 50 gallon drum but I'm not considering two after reading this thread. For now, let me know what you think is the best way to clean this thing. This is my first official post on R2R so looking forward to the responses.