The best way to clean urine out of underwear is by first soaking the garment in a pre-treatment cleaner for at least an hour, followed by machine washing it on the hottest water setting recommended on the garment's care label. For white underwear, bleach can also be used, but it must be diluted to prevent skin irritation. You can also use natural stain and odour removers such as white vinegar and hydrogen peroxide, as they don't contain harsh chemicals or irritants.
Pre-treating your underwear breaks up the stain, which allows it to easily wash away once put it in the washing machine. Popular pre-treaters require little work to effectively remove the stain. Apply the stain removal powder to the stain mixed with water, followed by rubbing the stain and letting it sit for 10 minutes. Other stain removers spray directly on to the soiled area. Once the time has passed put the underwear in the washing machine with your usual washing powder and one to two scoops of stain remover.
If your underwear is white it is safe to use bleach, or you can use a colourfast bleach on coloured underwear. To remove the stain, pour three to four drops of bleach on to the stain, gently rub the stain and machine wash it as usual on the hottest setting as directed on the garment's care label. You can also mix 250 ml (1 cup) of bleach with 500 ml (2 cups) of tap water in a bowl and allow the underwear to sit in the bowl for 10 to 15 minutes. Wring out the underwear and wash it as usual.
Natural cleaners found around the home, such as white vinegar and hydrogen peroxide will safely remove urine stains and odour from your garments. Urine can be removed by mixing 50 ml (1/4 cup) of white vinegar with 250 ml (1 cup) of water in a spray bottle, then spraying the stain and gently rubbing it. Allow the mixture to sit for 10 minutes, followed by washing the underwear according to the garment's care tag. If the stain remains, pour 5 ml (1 tsp) of hydrogen peroxide on to the stain and wash again.