Use a sterilised jar, four washed, unwaxed, lemons, and some sea salt. If you can't get unwaxed lemons then soak your lemons in a solution of warm water and vinegar and give them a really good scrub to remove all the wax.
Cut off both ends of the lemons.
Put a thin layer of sea salt at the bottom of your sterlised jar then pack the lemons in very tightly by putting the open ends of the lemons in first. I use a pestle that goes with my mortar to push them down as hard as I can. As you press lots of juice will begin to ooze out of the lemons. Seal the lid tightly and place the jar in the fridge. The juice from my lemons completely filled to the top of the jar, but if necessary, you can use a small amount of cooled pre-boiled water.
In four weeks I intend to make, a new to me recipe, called Date and chickpea tagine using these preserved lemons - so stayed tuned.
To use the lemons: rinse and dry however many quarters you need. Discard all of the flesh & pips and just use the skin. Slice this into whatever size you prefer. If the lemon liquid does not taste too salty it can be added to olive oil, balsamic vinegar, a little sugar and then made into a salad dressing.