DIY refillable Liebherr charcoal filter (and other filters)

I went looking for a replacement activated charcoal filter for a Liebherr refrigerator today and was appalled to discover that they sell for $45. Direct from Liebherr, they are $54.43 retail + tax/shipping = $70.49.

These tiny plastic bayonet-mount charcoal holders are just over an inch in diameter and serve no purpose other than to hold a few dozen pellets of charcoal. I’m supposed to throw it and pay $45-70 for a new one every 6 months? It turns out that you can just pry the perforated lid off (I used a dental scraper tool) and refill it with inexpensive activated charcoal. I bought a $4.59 tub of aquarium charcoal and am set for the life of the refrigerator.

Mine is a Liebherr freezer charcoal filter model 9880980 (putting this in here for search engines to find).

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