How do you get green tinge out of cotton?

[CalicoPusscat]

I've tried a bleach soak hot water bath nothing is working

Bleach is a bad choice as it can destroy structure of the fabric, do whatever you do next you need to be careful/gentle with it.
Is it pure cotton?

Why is it green tinged?
What is it?
Sunlight can lift a lot of stains
Sodium percarbonate is an eco bleach ( active ingredient in vanish but can be bought as a single product)
I've always been told cold to lift stains as hot water can 'set' a stain .

I agree with PP, sodium percarbonate. Have you washed the garment with hot water? As that may have 'set' the stain and you'll have quite a task to remove it.

Oh dear - yes I did use hot. It's 100% cotton. I'll see what I can do thank you

@CalicoPusscat
Could you cold soak it overnight in the bath ( you haven't said what it is) with either salt ( loads!) /sodium percarbonate (vanish etc) so it has an extra long time in tht solution? Then cold wash it. Dry it as close to sunlight as possible.

@Hskatkat it's not too bad but I'd have difficulty finding sunlight this time of year! It's just not as fluffy snowy white as it once was

It's like this. I'd washed a green coat previously then put on a white wash so it got a tinge.