The purpose of regenerating a BMC filter, a procedure which we recommend carrying out about every 20-25,000 kilometres, is to eliminate impurities from the filtering surface so that it can be used for the entire service life of the vehicle on which it is installed.
When re-applying oil to the filter, you need to previously wash the filter itself by following the procedure indicated above; also make sure there are no impurities or dirty oil residue on the filtering element.