Sidewalk and Driveway Salt
Only use the minimum amount needed according to the directions. A 12-ounce cup of salt covers about 250 square feet, which is about the size of a 20-foot driveway or enough to cover ten sidewalk squares.
Sweep up and reuse ice melt, de-icer and road salt if possible. Salt that cannot be reused can go in the trash.
Clean Water MN: Using sidewalk salt responsibly
Minnesota Pollution Control Agency: Snow removal: Do it better, cheaper and pollution-free!