How to whiten white clothes?

rewash in a color catcher that will pull the stain color out

Use Oxi-Clean. Place a small capful into the empty washing machine, place the clothing on top. Cut your other detergent in half or less as the extra soap is what causes clothing to go dingy. Turn on the machine to its regular wash cycle. I add vinegar to the softener cup rather than softener and it removes all of the extra soap and the clothing comes out fresh and soft. I use the cap that comes with iced tea as it is perfect in size.

Hi Joyce, perhaps this article will help: https://considerable.com/how-to-wash-white-clothes/