One of my sons left a ballpoint pen in his pocket, when though the wash and stained all of his school uniform pants. There was no way we would afford new pant for the kid at $35.00 a pair.
So, I went to Wal-Mart and purchased all the rubbing alcohal I could find - probably close to 5 gallons. Poured it into a rubber tub and let all the pants soak for 48 hours. I would 'stir' them up everyone time I was in the laundry room.
Anyhow, they come out as good as new. Hope it helps