Pour the liquid laundry detergent into the 20 oz. bottle. Use your own homemade formula or a base soap made from standard liquid castile soap.
Add the vegetable glycerin to the glass bowl. Microwave the bowl on high for two minutes. This melts the gelatinous vegetable glycerin into a thin liquid.
Stir the borax into the thinned, warm vegetable glycerin. Borax is a natural material sold as a laundry booster. It also adds to the thickening of your liquid laundry detergent.
Pour the blended, warm concoction into the bottle containing liquid laundry detergent. Secure the lid on the bottle and shake it vigorously for two minutes. This disperses the ingredients fully.
Remove the lid from the bottle to allow the solution to continue to cool. It needs to cool to room temperature with the cap off for at least two hours. As it cools to room temperature, it will thicken into a condensed gel like laundry soap.