A cover for a disposable oil filter. The cover includes a flexible insert for inserting into the flow hole of the oil filter, a cover plate fitting around the insert for pressing against the oil filter seal, and a fastener for retaining the plate against the filter seal. The insert includes a flexible head which may be pressed through the filter flow hole but which will prevent the insert from pulling back through the flow hole. The fastener is used to clamp the cover plate against the filter seal.