I've just recieved a beer engine from ebay, and was testing it out last night, just pumping some water through it. Bascially I got a load of crud coming through, small particles of black stuff. After a while the amount decreased, but every so often some would come out again. The beer engine itself looks to be in good condition, so I'm guessing it just hadnt been used in a while & there was some old beer left inside which had dried out. Whats the best way to clean it? Should I just pump some oxy cleaning solution through it and leave it to soak for a while? I'm really hoping I dont need to strip it down & take it apart..!