Towels, how to whiten them without bleach: it’s very simple

Another substance with powerful bleaching and degreasing properties is vinegar. To soak towels for many hours or even overnight, just pour half a glass into a basin of hot water. After that, wash it normally, either hand or in the machine. You may also use vinegar to get rid of unpleasant smells.
An eco-friendlier and more efficient alternative to vinegar is citric acid. Just mix 150 grams of citric acid with 1 liter of hot water. When you are ready to wash your towels in the washing machine, add about 100 cc of this mixture into the tub. If you want to do it manually, all you have to do is soak the towels before rinsing them.
You may think of sodium percarbonate as a greener alternative to bleach; it’s a cousin of bicarbonate. Putting a measuring spoon into the detergent drawer is the ideal way to use it in the washing machine, but you may also dissolve it in water at high temperatures exceeding 30°. Another option is to bring the water to a boil and then add 2 teaspoons of sodium percarbonate to the pot.
towels that have become wet
To use a lemon in a standard washing machine, just chop two slices and add them to a liter of boiling water. Soak the towels in the mixture for half an hour, and then wash as usual. To make a lemon-water combination suitable for use in a washing machine, combine half a glass of water with half a glass of lemon juice.
Hydrogen peroxide: While not exactly a natural technique, it does the job when it comes to bleaching. To wash the towels, just put a tablespoon of hydrogen peroxide in the washing machine. Be cautious to only wash whites in the washing machine and use a little amount of hydrogen peroxide.
But the number one piece of advise is to never wash your garments without first reading the label. You should probably avoid using the washing machine on certain garments and wash them by hand instead. To get your towels looking like new again, use one of these methods.