Aston, me thinks you talk out of your avatar!And I mean that in the nicest possible way.

Plenty of helpful tips in that link. If you have a dishwasher, try d/w powder or liquid. Put directly onto the stain and soak in very warm water. It gets all the cricket whites clean and grass is a bugger to get out. If not, plain household soap dipped in hot water and rub the area which is stained.
Not good for delicates though.

Dye it the same colour as the stain

wear it inside out

I've already got a broon top that's why I bought a yellow one


You can still see it.

take it back to shop , say it was there when you got it home

you actually tried it inside out ?

That's how I saw the stain was still there because it was inside out when I was hanging it on the line. Make a note to yourself to do that with your tops when you get here bacause the sun fades everything.

best not to wear one

me i meant