Borax Uses... all-purpose cleaner. Apply mixed..1/2 cup borax per gallon of water Disinfect the garbage disposal Carpet Cleaning Toilet Bowl Cleaner Clean mold and mildew Clean the floor cleaning outdoor furniture Clear clogged drains ... used apply Pour 3.5 oz (100 mg) of borax down the drain, then add 13.5 fl oz (around 400 ml) of boiling water. Let sit at least 15 minutes and flush with several more cups of boiling water.