This is another of those kitchen hint "recipes"! You might want to make a nice Moroccan dish, or some recipe calling for a preserved lemon, which you do not have at hand. This little recipe is supposed to help you out.
Slice the lemon from the stem side down into quarters, but try not to cut right though -- keep it attached at the bottom end.
Put it in a small bowl with just a little room at the sides (non-metal, non-plastic; glass is best). If you don't have a suitably deep bowl for an almost whole lemon, cut the lemon right through into 4 separate quarters.
Sprinkle over the salt.
Boil water in a kettle and pour it over the lemon or lemon quarters. Use a weight or weighted-down small plate to keep the lemon submerged.
Leave for an hour or more. You can try, over VERY low heat, to keep the liquid hot, which works better.
After an hour, especially if the water didn't go cold, the rind and flesh should be tender. Use in your recipe.
(This is just a quick and easy substitute for real pickled lemons!).