Discoloured collar and cuffs on school dress

[AnyDream]

Astrid, what's your soaking method? I would go hottest water you can for 2 hours then into a hot wash. Not all the time, just every now & again to juice ip the whiteness. I dont think they work so well if you just add it to the normal wash without the soaking. I've used lots of different brands and they all seem to come up ok.

[Astrid]

Normally the enzyme based powder, but in warm water (I thought very hot killed the enzymes )
Wash is just whatever seems right with the washing machine, think I normally pick the synthetic wash as it is poly/cotton.