Is the washing machine a valid means of purifying clothes that have become mutanajjis, such as throwing a garment that has a semen stain on it?
If the washing machine washes with pure/absolute water at least once, then the garment becomes pure provided that the semen has been fully removed. Note that if you add detergent the water becomes mixed. Therefore, if your washer washes multiple times, meaning that after it completely washes off the detergent from the garment, it starts to pour pure water and washes it once again, then the garment becomes pure.