If you live near a non-polluted source of salt water you can make your own sea salt -- simply gather salt water in clean milk jugs or soft drink bottles, pour it into a large pot through cheesecloth and/or a sieve to remove any sand or debris, and boil until 90 per cent of the water has evaporated. Then pour the thick salt water (it should look like wet sand) into a shallow baking pan and leave uncovered for three-to-five days, stirring occasionally.
Culinary blog How-to Baker used 22L of water which yielded around six cups of sea salt. The author notes that the time spent boiling is one to one-and-a-half hours per 3.7L of water boiled and also points out that boiling the water will kill any bacterial malefactors that may be lurking in the water. For step-by-step photos and detailed instructions visit the source link below.
Once you have your DIY sea salt you can use it to make flavored dipping salts, layer herbs in sea salt to preserve flavour and appearance, and make your own bacon salt.
How-to Make Sea Salt [How-To Baker]