I grew up in the 1950s. Our neighbour was an old-school upholsterer. To dull shellac, Charley used fine tripoli applied using a brush akin to a large shaving brush, and I've continued in this tradition, albeit applied using a soft toothbrush. Fine
tripoli can be bought on Ebay. It carries a risk akin to silicosis, so avoid skin contact and breathing in its dust.

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