First, fill your container with epsom salt almost all the way, or to how much you want it filled. After you get the right amount, pour into first bow. Now take the second bowl and fill with about 1/4 Cup water
In the water, add about 3-5 drops of your food color, and mix around. Now add about 1/2 of a tablespoon of oil. If you do this much you get a very strong scent, so if you want less, add less. mix this with your water
Now very carefully, or with a funnel (recommended) pour the water into the SPRAY bottle. Make sure the spray is on the wide setting, not the dart.
Now, carefully, with mixing the Epsom salt bowl with a spoon, spray the liquids into the salt about 10-12 times, so you get a good color layer on the top, mix this well. Keep doing this until it is all thoroughly mixed.
Make sure you don't have any huge chunks, or anything and carefully pour into your jar/container. Screw top on tightly and shake and shuffle about, so everything really is mixed. And now you have bath salt :) I gave mine as a gift, and the recipients seemed to like it. Or use it for yourself ;)