I finally gave up trying to use my Melitta coffee filters in my Chemex coffee
maker. The drip ended up too slow, and the filters had the unfortunate tendency
to break. The Chemex filters are more expensive, but work perfectly as intended,
so that's money well spent. This switchover started when (another) coffee carafe
broke. And while I don't have a spare carafe, I now have a Melitta cone and a
bunch of filters as backup in case I break the Chemex. Besides history
suggesting this will end up suffering a catastrophe at some point, as I
mentioned before, the glass is lightbulb-thin, so it seems inevitable.