I wonder.. Here where i live, glass and pet bottles recycled. Now petbottles are crunched and the plastic is used to manufacture lower quality (not sure) plastic.
Glass beer bottles etc. Are still reused.
So how bottles are cleaned? Nobody knows how bottle is used before someone returns it...for glass bottles there are more effective cleaning methods than for pet bottles. I guess.
But how did/does beer and other drink factories check whether one bottle contains some poisonous chemical?