Slightly odd question here but does anyone know how you could clean a white cotton top that has gone off white / yellowy due to age? I haven't done anything yet, trying not to make it worse. A google search brings up all kinds of advice from bleach to lemon juice but the wisdom of MN beats Google any day 
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I have to find a sailor costume for DD2 by Thursday and the only suitable thing I can find is a little sailor top that I once wore to a wedding when I was little. The navy part has kept it's colour perfectly, but the white is yellowish, and looks a bit yuk tbh, though it's not actually dirty as hasn't left the wardrobe for 20 + years (OK Nanna, you win. You were right not to throw it away! )