If you are a bleach positive.
Bleach sheets in washing machine. No chlorine bleach or added dyes. If you presoaked the comforter in the washer set the machine to Washing a down comforter with. New front loaded calorie.
Add suitable detergent and turn on the washer. Run a wash programme which operates at 90C with an empty load and add in some bleach. Baking soda and white vinegar are both natural whiteners and softeners that can be used when washing your sheets.
Dont mix towels with your sheets. Soak your sheets overnight in a laundry booster like Borax or OxiClean. Bleach should generally be added later in a washing cycle so that the detergent can do its job first without interference from the bleach and vice versa.
According to Style At Home you can add half a cup of baking soda with your detergent at the beginning of the wash cycle. Wait didnt I just preach about the dangers of chlorine bleach on white sheets. Take a large sink container and add water.
If your sheets have already yellowed try the following method. Wanna see how I get bright white sheets for my white bedding to always look fabulous after every wash. Put 60ml of neat bleach into the detergent drawer.
And then distilled white vinegar added to the washing machines bleach compartment. Soaking overnight in a borax solution can also help bring dingy sheets back to life again. Great for home travel college and hand washing.