These fragrant spheres for the bath (we scented ours with peppermint oil) are made by packing Epsom salts into a plastic mold.
Source: Martha Stewart Living, December 2008
The bath "snowballs" can be tinted any color. You'll need 3 to 4 days to make the bath balls because of the drying time between steps. Makes 2 large or 4 small balls.
To package the bath snowballs as a gift, use a glass kitchen canister to present the bath balls, which the recipient can then display on a vanity. Wrap the jar with ribbon, tying a bow at the top, and add a vellum gift tag threaded with cord in a matching color.
2 cups Epsom salts
2 tablespoons water
A few drops essential oil(s)
1 drop food coloring, plus more if desired
Special equipment: plastic pipette, large or small round bath-ball molds, storage jars
Stir together Epsom salts and water in a mixing bowl. Using pipette, add oil, 1 drop at a time, until strength of scent is to your liking. Add food coloring, 1 drop at a time, until desired shade is achieved; stir until color is even throughout.
Spoon a generous amount of mixture (more than necessary) into 1/2 of a bath-ball mold. Pack firmly. Repeat, packing mixture into second half of mold. Press pieces together until they connect. Remove top half of mold very carefully. Let bath ball stand, mold side down, overnight (set ball on an overturned jar lid to keep it from tipping over).
Remove mold carefully. Invert, and let ball dry completely, 2 to 3 days more. Transfer to jars.