It took a bit of trial and error to figure out how to use this properly, but once I figured it out, it really works well. I only have to apply it once every two weeks, and I have a clear mirror after my shower every single time. Here's how to do it:1. Clean your mirror well with glass cleaner and let dry.2. Take a shower. Spray a few pumps of this product on the foggy mirror, and wipe it all around with a clean, lint-free cloth. Do NOT rinse the cloth and wipe again, or use a fresh cloth to get all the sudsy bits off. The suds will dissipate on their own within a few minutes. The whole point is to get a layer of the product on the mirror - so if you wipe it off, you reduce its effectiveness. I just brush my teeth while the suds dissipate - takes 2-3 minutes, and by the time I'm done almost all the suds are gone and I can see well enough to shave or whatever.3. The next time you take a shower, the mirror will be miraculously fog-free. Do not wipe the mirror with anything - if you do, you'll wipe off the product and it won't work the next time. If it starts to fog again, repeat from step 1 or, in a pinch, just do step 2 and clean your mirror later.Oh, and by the way, this seems like it's very expensive at $14 for 32 oz. But I use two squirts every two weeks. This one bottle is going to last me for years. It's well worth it.