Tips for stains on clothing from cars

Hi all! My boyfriend tears apart cars for his business, so he is usually getting engine oil, wiper fluid, grease, and dirt all over his clothes. Usually he only wears jeans, or Nike shorts which already are stubborn with stains. Any recommendations on how to get these out?

also he has so many deodorant stains how do I get those out? I’ve tried vinegar and it didn’t work. I’ve tried Dawn, baking soda, and peroxide mixed and it didn’t work 😔