Discolored Case Causes
Sweat, breath, skin oil, saliva or any other body emission that comes with sleep can soil a pillowcase. Wash your pillow and any protective cover as needed to limit transferred soils to the case. It's fine to use bleach to sanitize or deep clean sheets and pillowcases but because of its potency, bleach also can cause pillowcase discoloration or yellowing; use bleach only occasionally and as directed on the label. Wash and dry bedding on cool or tepid settings; using hot wash water or a hot dryer sets stains, leaving them discolored. Borax or washing soda helps to whiten fabric and remove stains.