Some home remedies on here are a good idea. I don’t think this one is. Dishwasher tablets contain a lot of grease-busting chemicals to clean dirty pans & plates. It’s why they’re good to use when cleaning an oven door or hob. Your washing machine shouldn’t have a lot of grease in it. But it will have limescale, soap scum buildup, bacteria , and possibly mould. That’s why some people are reporting that when they’ve tried it out they’re getting horrific smells coming from their machine. Buy a proper dettol washing machine cleaner for £3 that combats all the things I’ve listed above. Or use white vinegar & soda crystals for a cheap homemade solution - that works on limescale and bacteria.