How do I get grease stains out of a favorite sweater?

From a cursory internet expedition, I am seeing that spraying WD-40 on the grease spots, rubbing it in, and then cleaning it with dish detergent (Dawn), is a good way to get it out of cotton garments. I wouldn’t worry about the nylon and spandex.

Try Dawn. Wet the air with lots of cold water and directly apply about a quarter size amount of soap to the stain, working it in gently with an old toothbrush. Allow to sit for 10 minutes and wash in cold water.

You may have to try several things, but make sure you don’t put it in the dryer, even on low. Heat set stains. I think GooGone specifically mentions grease.

Oxyclean

funny, i just got bicycle grease out of a pair of pants yesterday. here’s what i did:

wipe off whatever you can for starters. then cover it in baking soda, rub in with a little water. let it sit for 10 minutes. then pour vinegar over it for an exciting science experiment. keep adding and rubbing in the fizz. this gets the baking soda into the fabric a bit more. rinse.

put laundry detergent on the area with grease and rub in by rubbing fabric against fabric. let it sit for 24 hours. wash in hot water. take a look at it before you dry it—once it goes through the dryer, the stain will be set. if it’s not out, i would repeat these steps and wash a second time.

Thanks for the detailed answer @jsilberg. Since I asked this more than a year ago, I actually already got the stain out using @mcbealer‘s method. I’ll keep that in mind also though.