Making your own salt might be something that you would never consider doing, but it is an incredibly simple process. Not Without Salt is a blog dedicated to all things salty, and they provide some very simple anyone can follow to make your own salt.
First you need to gather some sea water – glass bottles are ideal for the purpose. When you get home, filter the water through at least four layers of fine muslin or cotton cloth to remove any impurities. You should be left with clean (but salty!) water.
Gently boil the water until it is all evaporated. To save energy, you can also place the solution in the biggest and shallowest dish you can find. Put it in a sunny place and allow the water to evaporate naturally. It will take longer, but your salt crystals will be larger. Once all of the water is evaporated, you have salt that is ready to use. Store it in a sealed glass container and use as needed.