In my old theatre company we used ordinary (top quality) hand-dishwashing detergent to get rid of all the grease paint and sundry dirt that gathered round the collar. The trick is to
wash up as soon as possible to not let the stains settle in. We pretty much ripped the shirts off the actors as soon as they got off-stage.
Just squirt the detergent on the stains and rub rub rub in scalding hot water.
I'm not joking about the as soon as possible. It's grease. It gets rancid. Rancid grease does nasty things to the fabric, and if you let it stew for too long the stains will never ever go away. Blood and grease stains should always be dealt with ASAP.