Bringing back the white in a T-shirt

[mfh]

DP put cheap new black shirt in the wash with cheap new white T-shirt. Result: T-shirt no longer white.

Can anyone suggest what I can use to make it white again?

If it's just plain white cotton you could try soaking it in bleach before washing it.

my mum has things like sheets in the washing machine and it acts like a magnet

actually I think it is called colour magnet

Glo-white, I think its called. You can get run-remover from the washing powder aisle of the supermarket - I used it when i washed the Christmas (white) tablecloth with a plum cushion cover by accident. It took 2 washes to turn a tie-dyed plum tablecloth back into a sparkly white one again.

colour run remover

they are like the sheet things that you can put in tumble drier.

Thanks folks! I couldn't remember what these products were called. I'll look for them in the supermarket at the weekend.

Colour run remover is like a little sachet of thick green liquid, as a regular laundry cocker-upper I can vouch for them ! Also to revive normal whites (stuff that hasn't had a colour run incident) then those GLO-WHITE whitening sachets are really good too. I put one in with my all white bedding every few washes and it really does keep them looking snowy

Never found anything works (and I have a cupboard full of various stain removing products) except soaking in a bucket of bleach.