Have you had trouble with your salt clumping up in the shaker due to moisture? The humidity in the air can create this problem to you because salt can absorb the moist very well. If you keep the salt in the closed container, it should be fine. But for the salt shaker, how can we solve this problem?
Japanese housewife suggest us to add a few grains of rice in the salt shaker. Rice can absorb moisture faster and more efficiently than the salt does, so it keeps the salt from getting moist. With this tip, your salt will flow smoothly every time you use it.
Source: Dako Magazine