How to get this cap white again?

[AdmiralButterfly]

It is cheap polyester but he adores it and the shop we bought it in is 200 miles away. (It is a bit wet hence looking two tone, main problem is it is filthy)

Can it not go through the washing machine? I'd use the sort of things I'd use of school shirts (always filthy!)

Add stain remover power to the washing power, and go over the worst bits with the soap bar that vanish do

Polyester's tricky cause you can easily ruin it. You can't use normal bleach on it. I take it this is a white cap that's been inadvertently dyed blue in the wash. You can try soaking it in a solution of Vanish or Oxi Bleach. These are oxygen bleaches and you can safely use them with polyester. There are some dye-stripping products,but none I've seen are safe for polyester.

It’s white. I think it just looks blue in the pic. The label says no bleach and no washing machine. It’s a cheap thing but ds loves it but has managed to get while thing super grimy

Label

Either stick it in a sink full of diluted Milton for 20 minutes or put it through the wash. It'll be fine as long as you re-shape it while it's wet.

Sponge the dirt off with washing powder solution then leave to dry in full sun for a day or two.

What about using Glowhite? Then hang out to dry in the sun.

Top rack of dishwasher apparently and it'll retain its shape... saw queen of clean do this on Instagram haven't tried it yet!

Would be acceptable a replcement?

Is it Headwear RC80X Houston 5-Panel printer's Cap Blank Plain amzn.eu/d/37WLrzQ this?

Try again...
this?

Perhaps hand wash with some napisan and fairy liquid-wash with an old toothbrush. peg it in the washing line in the sun-I just got what I thought was an unremovable stain out by hanging it out in the sun and it bleached it right out!

If its a cheap hat it will probably have some type of card in the peak which won't survive being submerged in water very well.
It might be worth hand washing the rest of the hat and cleaning the peaks with a damp cloth.

Thanks all. I gave it a sponge down with a dokter power sponge and it seemed to do the job for now. Next time he’s getting a black one!