Summarize this article in one sentence.
Glycerin is often sold in supermarkets, craft stores, and beauty stores in a 2 lb (0.91 kg) block. Once you have the 1 lb (0.45 kg) block of glycerin you need for this recipe, you can save the other half for another saddle soap mixture in the future. If you're storing extra glycerin for future use, you can wrap it in plastic wrap or wax paper, and store it in a cool, dry area. The small chunks of glycerin you cut do not have to be perfect or even. Cut the block into small chunks the size of your thumbnail. These smaller pieces will melt more quickly in your microwave. Place the small chunks of glycerin in a microwaveable bowl. Heat the glycerin on medium power for 30 seconds in your microwave, then remove and stir. Keep microwaving in 30 second intervals until the glycerin has melted. A 1 lb (0.45 kg) piece of glycerin will make approximately 2 cups (470 mL) of liquid when melted. Stir continuously to combine. To make a scented version of saddle soap, replace the milk or cream with 0.25 cups (59 mL) leather cleaner (not leather conditioner). Stir in a few drops of scented essential oils. Cream-based saddle soap made with animal fats and protein, like milk, condition leather well. Make sure you scrape any buildup from the sides and mix it in as well. It will begin to thicken as it cools. Once your soap mixture is becoming harder to stir but still able to be poured, it’s ready for storage. Let your saddle soap cool for an hour or two before sealing the jar or container. When it is hard to the touch, it has set and is ready to use. The glycerin will prevent the milk or cream in your soap from going rancid. Make your saddle soap last longer by storing it away from water in a cool, dry place.

Summary:
Cut a 2 lb (0.91 kg) block of glycerin in half. Cut the 1 lb (0.45 kg) block of glycerin into smaller chunks. Melt the 1 lb (0.45 kg) of glycerin in 30 second intervals. Stir the 0.25 cups (59 mL) of milk or cream into your mixture. Stir your soap mixture until it begins to thicken. Pour the mixture into your jar or container.