After doing your laundry, keep the door/ lid of your washing machine open for a few hours to give it a chance to dry out. If your machine is already infected you'll need to start killing the mould inside so run an empty hot cycle with a generous dash of Eco-Sentinel with a little of your preferred laundry detergent. After make sure it keep it mould free by using a dash of Eco-Sentinel with every load and putting a few drops in the machine after use.