When I was in my twenties I worked as a carb rebuilder and the shop owners flushed carb cleaner down the drain every day. You know, the kind that comes in a five gallon bucket and has a basket to dip the parts in. Very nasty stuff. But then, these guys were really behind the times. They took cash only and refused to work on any non-American car by telling the customer " we remember Pearl Harbor". This was during the 80s .
gus