with a grain of salt

Attic salt

Pointed and delicate wit.

covenant of salt

A long-lasting agreement.

go against the grain

To defy convention or norms; to do something in a manner that is unusual or out of the ordinary.

grain of truth

Synonym of kernel of truth.

not worth salt

Worthless.

old salt

A seasoned sailor, especially one who is hardy and forthright in manner.

rub salt in someone's wounds

To make a painful situation even worse (even with the best of intentions).

rub salt in the wound

To aggravate or exacerbate a physical or emotional injury.