Gojo works. THe white stuff is better than the orange, and not as likely to stain. Don't let it sit too long.
Stain stick.
Coca cola, believe it or not. Test it on something that's similiar with respect to fabric, but that doesn't cost a lot, or test it on a hidden part of the shirt. Let it sit for a while, but don't let it dry. Sometimes it's useful to soak the item first, wring it out, and then pour coke on it. You'd be surprised what coke will take out. (works well on blood, too).
If you're removing oil, be sure you're happy with the shirt before you dry it, because once it's been dried, it's set for life. I have lots of clothing stained with H-5606 and 120 weight oil as a testiment to a grungy life around airplanes, and mistakes made laundering clothes. (In fact, with the exception of my "office" clothes and the sunday monkey suit, everything I own bears distinct evidence of airplane contamination).
Personally, I believe white shirts around airplanes are a MISTAKE.