The Hario Woodneck brewer uses cloth filters that are not meant to last forever but I am looking to increase their usable age. As weeks pass, the flow rate of water through the filter noticeably slows down. In a brand new filter it seems almost constant from full to empty, but after a month or so the last bit takes ages to drain. What should I be doing to keep them 'alive' longer?
I am using the ones in the image if it matters. These are inserted to the hoop provided with the Woodneck.
Before first use I soak the filter in boiling water for a few minutes as instructed. After each use I rinse it with hot water. Between uses I store the filter in a ziplock bag in the freezer.