Using the analogy, they are like loose screws or other basic machine parts that fell down the pipe, got in the engine, jammed a bunch of things cause they aren'

Using the analogy, they are like loose screws or other basic machine parts that fell down the pipe, got in the engine, jammed a bunch of things cause they aren't supposed to be there, and consequently a bunch more misc scrap metal got sneezed out the exhaust pipe.