Measure 2 cups Epsom Salts into the large container. From that, take about 1/2 cup Epsom Salts, and put into the small mixing container.

Add food colouring to the 1/2 cup Epsom Salts. Using fork, mash colour into salts to blend well. Close with tight fitting lid and shake until well blended.

Transfer dyed Epsom Salts into large container. Close with tight fitting lid and shake until well blended.

Peel lemon and lime with knife or zester. Place peels into large mixing container. Close lid and shake well. Periodically shake bath salts to mix well during the next 24 hours.

Remove large pieces of citrus peels and compost.  (You may want to cut some of the peel into tiny bits to leave in the bath salts for decorative effect.  Be sure pieces are tiny enough to flow through a tub drain with ease.)

Transfer baths salts to decorative jar for later use or to gift. Store in a cool dark place. Shake before using.

Juice lemon and lime to make a drink or freeze in an ice cube tray for later use. 

Variation: To make (pink) grapefruit bath salts, substitute the lemon and lime for a large grapefruit and green food colouring for red.  To make orange bath salts, substitute the lemon and lime for a large navel orange and the green food colouring for yellow … with a couple of drops of red.