Diatomaceous Earth (DE) — is a naturally occurring, soft, chalk-like sedimentary rock that is easily crumbled into a fine white to off-white powder. This is in fact made from diatoms and can be used to destroy mites and other parasites. It literally cuts them to shreds, it can be used externally or internally. But if you use it internally you must be food grade, the stuff they use in pools is not safet to take internally.
Tip of the week.
Back in the 30's and 40's, engine oil filters were after-market items. At least one brand of filter used diatomaceous earth contained in what appeared to be a white cloth (or sack). A filter change meant that you replaced the goodly sized sack.
One day a 1939 Buick was pulled into the shop, its engine essentially destroyed internally.
Based on the looks of the oil, we pulled the top off the (you guessed it) diatomaceous earth filter. The sack was broken and diatomaceous earth had flowed with the oil and had its way with the the bearings, camshaft, crankshaft .. you name it. I was young and impressionable, and every time since that someone mentions diatoms I think of that Buick.
Then there were oil filters that used toilet paper rolls as the filtering agent. But I digress......