For a cheap grass stain remover that truly works, combine equal portions of white vinegar, liquid dish washing soap, and water. Shake well and work the solution into the spot. Let stand a few minutes and then launder as usual.
Also works on fruit or beverage stains.
This got all of the grass stains out of my son's light colored pants. I will never buy expensive stain removers again!
Source: The Queen of Clean by Linda Cobb
By windchime from Maple Falls, WA