Flush the filter with plenty of water, until the papery taste or smell is not apparent in the water coming through. I combine this with purging the receiving keg of O2 -- push the full keg of water through the filter.
(The papery taste can be from the filter, but also of course could be from or exacerbated by oxidation, hard to avoid in filtered beer. To address this, I give that flush water a healthy dose of metabisulfite to scavenge O2. )
EDIT Notice something that bothers me -- you say "fresh pads." You do realize that filter pads are single use, not able to be regenerated like the media in candle filters?