Iron-Out...
The stuff works so great it's unbelievable! No scrubbing. Just soak in hot water!
Pour some in 5 gal bucket, add a little detergent to the mix, then add enough hot water to cover pants.
Add pants, pour a little more in and use a broom stick to move around.
After a while the stains just disappear! The stuff stinks like sulphur, so move it to the porch or garage ASAP!
After they soak for a few hours or so, just wash as normal. I couldn't find anywhere locally, so I just ordered it on amazon.
You will not believe it! Son's pants that's he's wore in over 100+ games keep looking brand new!
You will be shocked and happy!