Help- bleached whites gone cream?!

[NedSchneebly]

I bleached my DSs White school polo shirt after he dropped choc milk down it. I soaked it in dilute bleach then put in washing machine on a quick wash with usual detergent. However it is now a rather unfortunate magnolia cream colour, and noticeably different from his others.

Any thoughts about why this happened, and what I can to to get it properly White again? I would like to be able to bleach his others, as they're getting s bit grubby, but don't want to risk having to buy new ones cos they're all cream! Can I just bleach it again?

Any ideas? TIA

No idea why it happened but similar happened to me and a lovely blouse I had - in the end I put it outside to bleach in sunlight ( which worked quite well) and then washed in the washing machine again at 60 degrees with bleach in the machine instead of soaking in the sink and it came out white - might be worth trying.

Thanks dinosaur- Will try that one. Did think to put out in sun. How do i bleach using washing machine? Never done that! :)