How To Make Your Own Dish Soap - One Good Thing by Jillee. 1/4 cup soap flakes or soap shavings (I used Fels Naptha.) 2 cups water 1-2 Tablespoons distilled white vinegar or lemon juice (I used vinegar.) 1 Tablespoon glycerin (optional) homemade dish soap Pour water and soap into a saucepan and slowly heat it over medium heat. Stir the mixture and keep heating it until all the soap has melted into the water. DO NOT let the mixture come to a boil. Turn down the heat if needed.