It is often recommended for cleaning blocked drains.
Caustic soda is often an ingredient of oven and toilet cleaners.
Don't use caustic soda to clear a kitchen sink, it will combine with with grease to form a hard soap which will block the drain. I mean store it. If you do get it on your skin, flush it with cold running water for at least 10 minutes. Alternative Pour vinegar or washing soda with boiling water down a blocked drain. Jeeves Whenever I am trying to find out how to do something.