Maybe the most used specialized cleaning agent in the Wrath household is the humble bag of sodium percarbonate. We have a lot of formal wear (shirts, uniforms etc.) that have seen decades of use and naturally turn yellow every now and then. I soak white garments in this (hot water), then sun dry (UV) before washing and rinsing by hand. It works extremely well and is cheaper that Oxiclean (same active ingredient). As it degrades to water and oxygen etc. it is relatively harmless to the environment. No nasty chemicals. For very delicate work like worn collars or lace I use a soft brush to work an equal mix of powder, dish washer liquid and hot water into the spot and then use a hair dryer to speed up the effect. Works like a charm while reducing washing machine wear and tear on valuable clothing items where no normal detergents can get rid of that yellowing.
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