I uses two pair of socks as a filter for my gen set on chargas. They acted like a kill switch the first time I got a little tar in them. Making charcoal - #153 by r_wesseling
Back in the day the old coalgas guys liked to draw the gas up through a column of lime chips. This would remove sulfur from the gas. Sulfur is corrosive to copper alloys and zinc. There are several cases on this site where the openings in throttle bodies have gotten to big so idle speed has increased (1). And @JO_Olsson had a brass throttle plate corrode to the point where a piece of it broke off and was sucked through the engine. ‘Sour gas’ has always been a problem in coal gas, natural gas, bio gas, and other gaseous fuel systems.
Rindert