Tip #1: I've found that original Dawn dish washing liquid will remove some grease stains even after they've been through the dryer.
Tip #2: Use hair shampoo to get grease stains out.
Tip #3: The key to getting out oily and greasy stains is to wash clothing in the hottest water that is safe for the fabric. 1. Remove as much excess oil as possible with a dull knife or spoon. 2. Apply 3-5 minutes to allow it to go completely through the fabric. 3. Use liquid detergent to rub through the stained fabric. 4. Allow the garment to sit for a few minutes. 5. Wash in the hottest water safe for the fabric. Check tags to determine what water temperature to use for washing. 6. Repeat steps 3-5 for fresh stains.
Tip #4: I've used Dawn original and Lestoil or PineSol also work well but check for color fastness. Let it sit for a few minutes then scrub well with your hands, wash as usual but don't use

water.
Tip #5: Cover the stained spot with a generous amount of baby powder. Leave it for 24 hours. Just throw in the clothes in the washing machine after. If the grease is still visible repeat procedure and put more powder this time.