Getting coloured clothes bright again?

Hellyboo

Hi all,
After just 3 weeks back at school one of my son's brand new yellow polo shirts has gone grey. I can't work out why because the other one (done in the same wash) is fine - the only difference was that the grey one had stain remover on it! Any idea on how to get it nice and bright again? Can I use something like Nappysan, as it's yellow not white? It does look like a colour run but as I said, it was done in a lights wash and everything else is fine. Very annoying! TIA
Hx

missmucksmum

This would be helpful to me too already chucked 2 tops and a third is now like this, my kids school changed from white to yellow this term x

PixieDust

You could try washing in vinegar to make sure all traces of soaps etc are out....?

Hellyboo

Have today been out and bought Ace washing bleach, biotex and colour catcher sheets all from pound shops, trying the ace first - will let you now how I get on!