Formula 420 is a great product indeed. It is acredited with cleaning my friends uncleanable bubbler, Ole' Drippy. For really dirty pipes there is nothing better.
However, make sure you rinse the pipe out well and wash your hands with hot water after using it.
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Si Vis Pacem, Para Bellum- "If You Seek Peace, Prepare For War."
"Those who would sacrifice liberty for safety deserve neither." ~ Benjamin Franklin