MLS Laundry magnets (washing without detergent) need absolutely no "sticking" to the water drum to work properly. There is a variety of washing machines, from front loaders to top loaders, and indoor washing drums ranging from plastic, iron and stainless steel. The material the water drum is made of does not matter, the MLS Washing Magnets (washing without detergent) work in all. The magnets may "stick" together during the washing process. This is perfectly normal and will not reduce their effectiveness, as they still emit the same level of magnetic force whether they are attracted to each other or not. The washing magnets only need to be submerged and/or close to water for maximum effectiveness.