My secret's my enzyme.
If you do your laundry at a laundromat or community machine that has a FRONT LOADER, the people before put too much detergent in the soap receptacle. The extra soap flows into this little overflow chamber and is slowly rinsed out in subsequent loads. So put your clothes in and put the money in and press start, the soap is already there. Doesn't work for top loaders where you put the soap directly in the wash basin, has to be a front loader machine.