Abstract: Heavy components of dead oil in tank are mainly gelled oil and wax, which can be blended with crude oil and transported after melting with hot oil above 50 ℃. Based on the property of heavy components of dead oil, the gelled oil can be cleaned by dissolving and flushing with hot oil. The flushing process should be conducted on the tightness basis with low oil loss and light pollution. Moreover, by this method, regular inspection and cleaning can elongate the manual or mechanical cleaning period to bring down the running risk.