Prilikom prijevoza sirove nafte u tankovima ostaje talog koji se sastoji od parafinskih i asfaltnih supstanci. Kada se tankovi ne bi ispirali došlo bi do velikog taloženja te bi količina taloga smanjila mogućnost ispumpavanja tanka. Također, došlo bi do smanjenja kapaciteta tanka. Čišćenje tankova veoma je važno kako bi se izbjeglo onečišćenje mora i okoliša. Postupak pranja tankova sirovom naftom obavlja se tako da se dio tereta sirove nafte koji je potrebno iskrcati provede kroz sustav za pranje tankova i to tako da se snažnim mlazom operu površine tankova, te da se talog sa dna pomiješa sa tekućom naftom i na taj način izbaci iz tanka. U radu je objašnjen sustav pranja sirovom naftom (engl. Crude oil washing) i načini ispiranja.

When crude oil is transported in tanks, a sludge consists of paraffin and asphalt substances. When the tanks were not drained and stripped, a large precipitation would occur and the amount of sediment reduced the possibility of pumping the tank. Also, there would be a reduction in the capacity of the tank. Tank cleaning is very important in order to avoid pollution of the sea and the environment. The process of washing tanks with crude oil is carried out so that part of the crude oil that is to be discharged is carried out through the tanks tank so that by the powerful jet the surface of the tanks is operated and the bottom of the tank is mixed with the liquid oil and thus thrown out from tanks. This paper explains the COW system and methods of flushing.