I always do a spot test. I did learn the hard way over the years. I have done some crazy things to mine and others laundry on the way to learning! There are some fabrics that this isn't great for. I did have really good results on some, mostly cotton, pillow cases that had makeup residue on them. After some guests had left I immediately went and stripped the bed to wash everything. Then to my own dismay I noticed some smudges on fairly new sheet set pillowcases. It was mostly just some eyeliner or mascara and foundation it looked like. I sprayed the pillow cases and let them sit overnight for the treatment to soak in. For me it is just something handy to keep in the laundry room in case of mishaps. For what I used it for it worked great.