In a large, high-sided saute pan, combine salt and rosemary. Place over medium heat, and warm through, about 10 minutes. Transfer salt and rosemary mixture to a container. Let cool 5 minutes, uncovered, and then cover with an airtight lid. Let stand at least overnight.
When ready to fill containers, discard old rosemary. Fill desired containers with salt, and garnish top with a fresh sprig of rosemary; seal containers.