Once oil stains have been “baked on”, as in they have already gone through a wash and dry, the only way to clean the stain is with something like lighter fluid.
I soaked the stain with lighter fluid and let it sit in the sink for several hours. Then washed it off and let it air dry. Wash it like normal one more time since it will smell terrible. The stain is barely visible now and while my pants would have been ruined before, they are now acceptable to wear in public. If it’s still socially acceptable for a grown man to wear shorts in public. When it’s 110 outside I like to pretend that it is.