Despite rock salt on the road, the going was still slippery.

Start doing weekly water changes of 10-20%, but don't add any more rock salt.

But perhaps they don't understand that rock salt is ineffective at -20C.

Then there is the annual failure to buy rock salt in time.

Rock salt is used to lower the freezing point of ice.

Near the town is an extensive deposit of rock salt.

I'm afraid they are going to eat the rock salt.

In 1692 a small factory was set up to refine rock salt.

It is not used much because it costs quite a lot more than rock salt.

It also sold more than 600 20-pound bags of rock salt, compared with 100 on a normal weekend.