In order to do so, you must be aware of all safety hazards. Children, pets and feeble-minded people should not be in the soapmaking area or have access to stored soapmaking ingredients, especially lye and essential oil. Put the fats in a lye-resistant container and place a glass or stainless steel thermometer into the fats. Be sure the thermometer doesn't touch the bottom of the container and give a false reading. Heat the fats and optional ingredients to the temperature specified in the recipe.
Cold water is important.
Stir the water and slowly add the lye. The water will get hot and turn cloudy. Continue to stir until the lye dissolves. If you wait too long to stir the water, the lye could harden in the bottom of the container. This is not a problem.