Drill 10 to 20 holes into the top of the stump with a half-inch drill bit. Make the holes at least half as deep as the exposed stump is high.
Put 1 cup of crushed rock salt and two cups of hot water into a blender. Blend on high until the salt completely dissolves into the water.
Pour the rock salt and water mixture into the holes in the stump.
Let the water soak into the stump overnight.
Sprinkle 1 cup of crushed rock salt into the holes the following morning.
Repeat the salt application process once every three months if you would like to rot the stump away. According to "Better Homes and Gardens," if you intend simply to kill the stump and stop further growth, one application will do the job.