1. Baby Powder
If you have a piece of clothing stained with oil, you can resort to the trick of applying baby powder where the stain is so that it is absorbed. Let it act for a day and then take it to the washing machine.
2. Dish Detergent or Shampoo
Cover the entire grease spot with liquid dish detergent. You also can use shampoo in this manner, as well, it's designed for body oils, so should work effectively in this application. Alternatively, use bar soap, any hand or body bar soap will do (make sure it hasn't got any additives that may hinder its cleaning, i.e. one like Dove would not be suitable), or for very tough grease, look for bars labeled Laundry Soap. Dampen with water (or ammonia for extra grease removal), then rub the bar onto the stain until sufficient soap has transferred to foam up amply. You can also grate the bar soap and apply the resulting powder/pieces onto the stain after wetting. If using colored detergent, be sure to dilute it or the detergent may stain the clothing. For stubborn stains, using an old toothbrush will help you attack the stain better than you'd be able to with your hand. Old foot brushes or nail brushes can also serve, as well as small scrub brushes available for cleaning.
3. WD-40 or Lighter Fluid
Instead of detergent, spray a little WD-40 or lighter fluid onto the clothing. WD-40 is effective in removing grease from some surfaces, as are some lighter fluids. Perform a spot test on an inconspicuous area of your clothing before attacking the stain with the WD-40 or lighter fluid. It's better to be safe than sorry. Let the WD-40 or lighter fluid set into the clothing for 20 minutes.Wash out the WD-40 or lighter fluid by thoroughly soaking the clothing in warm water. Wash the clothing, alone, with laundry detergent. Follow washing instructions on clothing label exactly. When ready to dry, allow the clothing to air-dry. Drying in the extremely hot mechanical dryer may cause any lingering oil or grease to set into the clothing.
More information: https-www.wikihow.com-remove-grease-or-oil-stains-from-clothing