6.5 Cleaning the Comyn oil/water Separater Finally, open drain cock to bilge and continue to pump clean water into the separator for a short period. Close valve and leave the separator full of clean water at all times6.5 Cleaning the Comyn oil/water Separater • Finally, open drain cock to bilge and continue to pump clean water into the separator for a short period. Close valve and leave the separator full of clean water at all times