If you notice that your mattress has yellow spots from sweat stains or that it otherwise seems dingy, lightly spritz the affected area with 3 percent hydrogen peroxide until it feels damp but not soggy. Usually, you can simply attach a sterile spray bottle nozzle right to the peroxide container. The discoloration will disappear as the peroxide air dries. And suppose you are unable to eliminate the discoloration for some reason. In that case, you should contact a certified mattress cleaning Australia professional and let professionals do the chore while you focus on what truly matters.