Break open the soap nuts with a hammer and discard the seeds. Cut the lemon into 8 pieces each and boil soap nuts and lemon in the water till the water is reduced to half. Let it cool and then strain the water. Grind the boiled soap nuts and lemon in a blender with some of the soap nut  water and strain to remove all the liquid. The pulp can be used to clean your brass and copper vessels. Boil the strained liquid for about five minutes and strain one more time. Once this has cooled add 1/4 cup glycerin, 1 cup vinegar and a capful of any essential oil of choice. I have used lemon essential oil to keep it consistent with the fresh lemons used. Add 1 tsp of xanthan gum depending on the thickness you prefer.  Xanthan gum is a food grade thickener and stabiliser produced through microbial fermentation.  Blend with stick blender till it becomes thick. Store in a bottle with a nozzle and use it to clean your dishes. Soap nut liquid has a shelf life of about two weeks. But I have added vinegar which  is an excellent cleaner and a preservative and I am hoping this detergent will have a longer shelf life.  Yield is approximately 750 ml of  liquid detergent.