i work in a restaurant, as a cook. we are allowed to wear jeans. the only problem is, i have a couple pair that seem to have absorbed some kitchen grease, and i can't seem to get them smell and feel of grease out.
I use Castrol Super Clean or ZEP degreaser. Home Centers, hardware, and auto stores carry it. Either will clean all kinds of grease including food grease. Wear gloves as they are strong alkali formulas and has not harmed any clothing of mine, yet.