It never fails when I wear a white shirt, I always wind up with some small stains on the front of my shirt. Last night, we went out to celebrate Stacey's birthday and I splashed grease and fat all over my shirt. Quite by accident the grease and butter from my ribeye steak splattered on my shirt.
And while I could have easily taken it to the cleaners, or to the office and have it cleaned for me, I decided to show you step by step how I cleaned it at home.
Step 1: Scrape off any excess fat or grease from the shirt using a spoon or a dull knife. Be careful not to spread the stain further.
Step 2: Sprinkle a generous amount of cornstarch or talcum powder on the stained area. Gently press it into the fabric to absorb the grease. Let it sit for about 15-20 minutes. 
Step 3: After the powder has absorbed the grease, brush it off the shirt using a soft-bristled brush or a clean cloth.
Step 4: Pre-treat the stain by applying a small amount of liquid dishwashing detergent or a stain remover directly to the affected area. Gently rub the detergent into the fabric with your fingers or a soft brush. Let the dish detergent sit on the stain for 10-15 minutes to break down the grease.
Step 5: Fill a basin or sink with warm water and add some mild laundry detergent. Submerge the shirt in the soapy water and gently agitate it to loosen the stain. Allow the shirt to soak in the soapy water for at least 30 minutes, or longer if the stain is stubborn. Rinse thoroughly with clean water to remove any soap. 
Step 6: Finally, wash the shirt in cold water with laundry detergent. Air-dry the shirt. Inspect the stained area for any signs of remaining stains and repeat cleaning process if any stain remains. Avoid using the dryer until the stain is completely removed because heat sets the stain. 
I hope these tips help you.
Marc