What to do with this discoloured skirt

[Dingdong99]

I have this skirt which I love, but for some reason it now has a slightly yellow tinge all over it

It's made viscose abs says wash wool cycle at 30 degrees

Any suggestions as to how I can fix it? It's one of my favourites so slightly upset!! Thanks

Have you tried putting it out in the sun? I’ve done that with difficult stains before but usually on cotton and linen fabrics so I’m not sure about viscose

Have you tried putting it into a wool wash with a Dr Beckman Glow white sachet?

That s a good idea! Especially with this weather. I'll pop it out tomorrow

Thanks x

Thanks Mad, do you think that'll whiten the black spots?