Try cutting down or changing your detergent; adding STPP; line drying in the sun; and most of all try washing in much hotter water. White cottons get 155 -185F in my house.

If you have been using a lot of bleach (sodium hypochlorite, aka Clorox) you may have removed some of the
Optical Brightening Agents. Check your detergent formulation and see if it is designed to redeposit them. If not try a change of deteregnt for that reason.

Yes, bluing is still being used. I keep some on hand but haven't used it in many years as the above steps, especially the hot water part, do the trick for me.

HTH,
L.

what???this??who?

Chlorine bleach will turn whites yellow and there's nothing you can do to reverse the damage.

I read this advice on line but I have my doubts, "To remove yellow bleach stains from overbleaching: Bear in mind that some stains will not come out. If you have yellow stains on white clothes from overbleaching, try using RIT Color Remover."

Moving forward, use oxygen bleach (sodium percarbonate) instead. If you use it from the start, your whites will stay white and oxygen bleach will not damage the color. I prefer a pure version (as opposed to OxyClean which contains fillers). Ecover has a pure version.

I use it from time to time on my whites. Mrs. Stewart's Blueing. Mix no more than 1/4tsp in 2qts of cold water and add to final rinse. Fabric softener should not be used if you use it. The rinse water will be slightly blue but the yellow tint in your whites should be gone.

For serious yellowed towels and linens/whites; you can also use Tide Professional Whitening Enhancer; if you don't mind buying a 5-gal pail of it. I have this as well. I purchased it from a company in NJ. I mix about 2-3Tblsp in 2qts cold water and add it to the 2nd to last rinse and it has really whitened up my whites; that said, however - you should note that Tide Professional IS an optical brightener, so the Mrs. Stewart's Blueing is a much easier and environmentally friendly way to make those whites gleaming again. I tend to only use the Tide Professional on our company stuff that gets really dingy and yellowed from using a lot of chlorine bleach.