salt in the wound

Attic salt

Pointed and delicate wit.

covenant of salt

A long-lasting agreement.

not worth salt

Worthless.

old salt

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

put a band-aid on a bullet wound

To inadequately treat a serious situation.

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.

salt away

To save or preserve (especially money) for future use.