Summarize the following:
Place a large pot onto a set of kitchen scales and set the display back to zero. Slowly scoop in or pour in your rendered animal fat until you have as close to 1 lb (450 g) as possible.  Getting the measurements exactly right is crucial, as soap-making and glycerin making rely on a precise chemical reaction. Not having the right amount of fat can lead to caustic soap or glycerin that can be very harmful. If you want to alter the exact measurements for your own soap recipe and the type of fat you are using, look online for a soap making calculator. There are plenty that will allow you to enter the amount and types of fat you are using and give you precise instructions for the right ratios. In a separate jug or bowl, measure out 5 fluid ounces (150 ml) of room temperature water. Slowly add in 2 ounces (57 g) of lye, stirring constantly as you do so to incorporate it fully. Leave the lye and water mixture to react and cool down.  The water and the lye will combine and create an exothermic reaction, meaning the mixture will heat up. You should always wear protective gloves and eyewear when working with lye, as it is a caustic substance that eats away at fat. If you get any lye on your skin, remove any clothing the lye may have touched and flush the skin with cold water for 15 minutes. Seek medical attention immediately. Lye may be available in the cleaning section of your local grocery store. It should be easily available online or at a specialty soap-making store. Use a candy or other food thermometer to check the temperature of your rendered animal fat. Place the pot over low heat to slowly bring the temperature up to 113 °F (45 °C) if it’s too cold, or leave it to cool down if the fat is too warm. Once it’s at the right temperature, remove it from any heat source. Keeping the temperatures exactly right will help the fat and the lye to combine properly, resulting in a smoother soap and clearer glycerin. With both the fat and the lye solution around 113 °F (45 °C), begin very slowly streaming the lye solution into the fat. Stir the solution in as you do, being careful not to splash the lye or get any on your skin.  It may be easier to get someone to help you stir the fat while you pour in the lye. Work on a sturdy, flat surface so that you can continue stirring easily while the soap mixture thickens. Once the lye solution has been completely mixed into the fat, keep stirring in slow, regular motions. After around 15 minutes, the path of the spoon should remain visible in the soap mixture for a few seconds. This is known as tracing and is a sign that your soap mixture has thickened and is ready. Rather than stirring by hand, you could use an electric mixer or a stick blender to combine the lye and fat. Start at a low speed to avoid splashing the mixture around too much.

Summary:
Weigh out 1 lb (450 g) of rendered fat into a large pot. Stir 2 ounces (57 g) of lye into 5 fluid ounces (150 ml) of water. Bring the fat to 113 °F (45 °C) and place it on a heat proof surface. Pour the lye solution into the melted fat slowly, stirring constantly. Mix the fat and lye together until the soap begins ‘tracing’.