stefan m. wrote:Would a thin construction net or something similar do the job? Because i know where i can find one of those...
Yes a construction net or a shade cloth will do. You can even swirl a batch in a bucket half filled with water and dump the water fast taking away all fines.
There are more cacti in heaven and earth, Horatio, than are dreamt of in your philosophy.
One of the few cactus lovers in Lebanon (zone 11a)
Molar clay or diatomaceous earth is used in some cat litters or in materials used for soaking up oil spills. However not all cat litters use it since some are just shredded paper and some the "clumping" variety that use a white fullers earth type clay. Therefore make sure you get the correct type and not just any cat litter. It is the hard baked clay like red/brown material you want.
I would suggest people look on their own EBAY to see what's available as diatomaceous earth or molar clay cat litter, or Google "Molar Clay Cat Litter" or "Diatomaceous Earth Cat Litter". There was a Bonsai site that used to list the suitable products available in most countries, however as our favorite UK one Tesco's Premium Cat Litter has now been withdrawn it has been taken temporarily off the Web. However those in the UK can still get Sophisticat, but the granules are somewhat larger.