This too! Same concept as the cornstarch, but what I have found is that it’s a lot less work to use cornstarch on soft stuff like clothes since it’s already powdered, and chalk is great when you get greasy spots on more rigid surfaces like your shoes. Perfect for canvas sneakers, even suede - just brush well after.
Anyone else use Murphy’s Oil Soap for this?
Felsnaptha bar soap. Scrub, then wash.
Seconded on the Dawn. Handy since I can’t seem to eat anything without dropping some greasy thing on my shirt. Guess I need a bib.
For really stubborn stains, make a paste of OxiClean and water, apply to both sides of the fabric, and leave overnight. The gel works pretty well, too.
I have had great success with liquid dishwashing detergent and hot water. You saturate the stain in the detergent, scrub the hell out of it, and rinse with hot water, and then stick it in the hamper until wash day. I’ve been able to salvage many items of clothing this way.
Goop or GoJo, like others have said, are your best bet. Fast Orange is OK, but use the smooth kind, not the pumice stuff. The only side effect of Goop or GoJo is a telltale UV signature under a black light!
Oh, wow, I didn’t know about the UV effect. That has the potential to be badly misinterpreted.
This is me. 
Another vote for Dawn. A couple of drops, rub it in good, leave it for a while to let it bond to the grease in the stain, then launder as normal. Don’t use too much, especially if you have a front-loading washer; too much foaming can cause problems with those. But it should only take a few drops.
I’ve even successfully used Dawn on grease spots that have been through multiple wash and dry cycles.