in a solution of soap and warm water overnight can help to loosen the food particles. you can fill up a sink or a small tub with a solution of soap and water to soak the trays. make sure all the trays are under the water’s surface. if the food residue on the trays is still stuck hard, you can try putting vinegar or baking soda in the water.
once the trays are done soaking, the food residue on the trays will be much easier to clean. you can use a large scrubbing brush to remove the toughest of particles. in case there are still any particles stuck to the trays, 