Wet & Forget takes such a long time to work that you might not realize you used it in the 1st place. The truth is rain will eventually get rid of many stains on surfaces without this ingredient so I’m wondering if it’s actually doing it’s job or should I give credit to H2O instead. The instructions say for stubborn stains you can reuse in a month but who is so concerned with stains that they put this on the top of the calendar. I for one forget what I ate for lunch yesterday so in my case it’s Wet & Really Forget.