Here are the steps I use to get grimy pillowcases clean again, including the yellow waxy grease bleach can't touch. This removes the stain and odors, too.
How to remove yellow stains from pillowcases in 10 minutes - get them 'bright white' again
The Ultimate Guide to Washing Down and Feather Pillows
Abbotson Linen King Pillowcase Pair White
Remove Yellow Stains From Your Pillows With These 4 Simple Ingredients
How To Wash Yellow Pillows (Step-By-Step)
How to Safely Wash and Care for Your Blissy Silk Pillowcase - Heritage Park Laundry Essentials
Cleaning expert's 29p hack to banish yellow stains from pillows and bedding - Mirror Online
Cleaning: How to remove yellow stains from white pillowcases and bedding
How to Wash a Body Pillow: The Step-By-Step Guide
Why Pillows Turn Yellow, and How to Clean Them
How to Get Body Oil Out of Sheets and Bed Odors