The best answer is to fill the bucket with a gallon of water and add 3/4 cup of bleach. After letting the solution sit for five minutes, put on your cleaning gloves and use a scouring sponge to clean the bucket. Empty the bucket and rinse thoroughly.If you clean with ammonia, you need to use a hot water and vinegar solution to clean your mop bucket. Do not mix bleach with vinegar, as this is highly dangerous!