If the grease has gathered on the basket(s) or removable trays, washing them in warm soapy water should be enough to remove the grease.
If the grease is stubborn, or you’re looking to get baked-on grease off the interior walls and non-removable components, make a paste using equal parts baking soda and water.
Rub the paste onto the grease and let it sit for 30 minutes. You should then be able to scrub the paste off with a soft-bristled brush and rinse it away with a damp cloth and warm water.