Hi guys, So I got a job lot of brewing stuff off ebay recently including 24 demijohns (the main reason I bid). Came with a box of odds and sods and looking through this morning this included some various brewing chemicals (pectilase, yeast nutrient etc). There was also a large bag of metabisuphite (can't remember if it was potassium or sodium but doing a bit of searching its roughly the same thing). Is this worth keeping. Not really sure what I would use it for... On the pack it makes it sound like a steriliser but not sure its held in high regard for that. Any suggestions?