nitre

As he that taketh away a garment in cold weather, and as vinegar upon nitre, so is he that singeth songs to an heavy heart.

For though thou wash thee with nitre, and take thee much soap, yet thine iniquity is marked before me, saith the Lord GOD.

And whilst they were eating and drinking, the butler and the baker remained there, and Pharaoh's ministers found many flies in the wine, which the butler had brought, and stones of nitre were found in the baker's bread.