Lestoil works GREAT for grease stains. It's getting harder to find, though.

If you haven't washed it yet sprinkle talcum powder on it and let it sit for a couple of hours. The talcum powder absorbs the grease and when you brush it off the stain is gone. This always works on fresh grease stains, I don't know about old ones. Something to file away for future if not now.

If it has been washed I second sweetbean. Lestoil is a great cleaner. but you might try anything that has a degreaser in it. Just test on an inconspicuious place to see if it removes the color too.

Fels Naptha is good too. Rub the bar on with warm water and massage it really well, let sit 5 mins or so.

I've had great results using "Goop" hand cleaner on greasy laundry spots.

Grocery and hardware stores sell it. You could also probably find it at an auto parts store, or maybe even the hardware aisle at Walgreens.

If you can't find Goop, I'd try Dawn dishwashing detergent.

Put either the Goop or Dawn right on the spots, then launder as usual.

Here is a link that might be useful: Goop website with laundry instructions

Try a product called "Awesome". You can buy this at the dollar store. Saturate the stain and rub it in to the material and let set about 5 minutes. Wash and let dry on line (not in dryer). If stain still remains repeat process. If it wasn't for this product, I wouldn't have any unstained close to wear!

Eucalyptus oil is great for getting out these types of stains. Just cover the stain with the oil and rub gently for a few seconds to allow it to loosen the stain and then wash normally. If it is really set and you can still see the stain once your hoodie is dry you may have to rub with the oil again and then rewash.