While it may seem like a lot, it is essential to thoroughly cover all of the green hair. Use any brand of tomato juice, as it does not matter. It is the acid in the tomato juice that helps to remove the color.
Before washing, cover all of the hair with tomato juice, allowing it to saturate fully. Massage it into the scalp to make sure all of the roots and loose hairs are covered. Let it set for several minutes.
Use water to rinse the tomato juice out of the hair. Wash the hair with shampoo to remove any lingering smell. Condition the hair as usual.