I have always used Ms Clairol (two different shades of Blonde.. light blonde w/a Golden Blonde... then had my daughter use Professional hair color & darken it.. to a Darker blonde last night... It turned A lot darker than we wanted w/a GREEN Hue to it.. HELPP :(

If you put tomato sauce on her hair then wash it off it should take away that greenish colour as red is opposite to green on the colour wheel. (I am a Hairdresser).

It gone green because you have taken all the red pigment out by the blonde, you can either do what the top comment says which will get rid of the green tint a little bit, or you can dye you're hair blonde gain, may be a bit damaging I know but what's better? Then dye it the colour with a cheap dye as they usually contain red pigment