You’ve cleaned it perfectly, but wet jugs are mold magnets. After washing, prop the lid open and invert the jug on a drying rack. For straws, stand them upright in a cup or hang them with a clothespin.
Never seal a wet jug. If you screw the lid on immediately, you’re creating a perfect greenhouse for bacteria to party until your next use. Let everything air-dry fully before reassembling.
If you’re in a hurry, use a clean paper towel to dry the inside manually. It’s better than trapping moisture. But honestly, air-drying is the most effective and effortless method.
