Over time, you may find that your bright white sheets start to show yellow discolouration, which can come from acids and salts in body sweat, lotions or improper storage. As long as the stains are not set, you can remove them with the right washing techniques. Unfortunately, some yellow discolourations occur because of a chemical reaction in the fabric and will never be removed.
Spray yellow stains with a mixture of equal parts water and vinegar to pretreat the discolouration. To remove heavy yellowing, combine 1 cup of regular dishwasher detergent (not lemon scented), 1/2 cup of washing soda and 1/2 cup of washing powder. Fill the washing machine with warm water, and allow the sheets to soak overnight, and then run through the normal wash cycle. You can dry the linens as you normally would.
Once the stains have been removed, keep them from reappearing by adding stain-removing agents every time the sheets are laundered. Add one scoop of oxygenated washing powder to your regular washing powder to remove regular build-up of sweat and oils. Alternately, add 1/4 to 1/2 cup of detergent, 1/2 cup of washing soda and the normal amount of washing powder to the washing machine and launder as normal. Either of these methods will help keep your white sheets looking white.
What Not to Use
One common cleaning agent that will not remove yellow stains on bed sheets is chlorine bleach. It works well to remove some types of stains, but bleach can actually cause yellowing in linens or make existing discoloured areas worse. Additionally, it has an unpleasant odour and can damage and wear holes in the fabric if too much is used.
Frequently wash your sheets to prevent yellow stains from appearing. Laundering them once per week will remove the oils and skin cells that cause the discolourations. If you wear little clothing to bed, you might want to wear a shirt or trousers to minimise the contact your skin has with the fabric. Wear clean pyjamas to bed every night; the clothes can absorb body oils and sweat that rubs off onto sheets if worn multiple nights.
When storing the sheets, ensure that they do not come in direct contact with shelves, which can cause yellowing that cannot be removed, depending on the type of wood stain used. The wood can cause the fabric to oxidise, which is especially true for sheets that have been stored for long periods.