Easiest way to remove oil stains from fabric?

Washing-up liquid. It's made to break down grease so it does the same on fabric. Blot off what you can, then if it's fresh cover it with cornflour or baking soda for 20-30 minutes to pull the oil out, and brush that off. Work a few drops of washing-up liquid into the spot with your fingers, leave it 10 minutes, then wash at the warmest temperature the label allows. Air dry and look at it before it goes anywhere near a dryer. Oil often leaves a faint shadow the first time and needs a second go.