says on the box NEVER to use a washed and un-oiled filter, as the OIL stops the dirt???? just lettin u know what it says,cheers, Rob
PS i would seriously reccomend a cleaning kit, leave it to soak, rise under tap, you will be amazed at the colour of the water that runs out!!! Brown, full of sh*te, and ur left wi a magic filter lookin like new!