I have had some white shirts and white pocket t-shirts hanging in the closet for a good while. They have "yellowed."
Does anyone know why this happens, and what is the best way to make them white again?
Thanks
It's oxydisation. You can try acetic acid neat on the area followed by a mild bleaching, if not completely successful. Other than that there's little you can do I'm afraid.
In the US, the Rit Dye people make some fabric treatments. You might try one of their fabric whiteners. Here is a link:
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