Like a traditional cleaning cloth, you use them dry for dusting and very slightly wet for more general cleaning, but you'll need to experiment! The first time you use one, force of habit will probably make you soak it with water and add loads of soap as well—both of which will reduce the cloth's effectiveness. I find the best way to use these cloths is with as little water as possible. If you're cleaning very dirty windows, for example, use a standard cloth and soapy water to wash all the dirt off first. Then rinse them thoroughly with clean water and use a rubber squeegee to get them almost dry, and let them dry in the air for just a little longer. At this point, with hardly any water remaining on the glass, polish over with your microfiber cloth—and you'll be amazed at the smear-free, sparkling finish. If your windows aren't too dirty to start with, simply use the microfiber cloth by itself with a little water. You can use microfiber cloths to clean virtually any hard surface. Try them on your bathroom or kitchen surfaces and you'll be amazed at the results. (Sorry to sound like a bad TV advertisement, but these things really are good!) You'll literally hear things getting squeaky clean and shiny.