They are more than likely stuck from grease take a butter knife and slid it between the hood and the screen and break the grease seal all around the screen then try removing it by pulling on the tabs at the same time in one direction away from the frame it should come out. You can go to Wal Mart and buy Super clean to clean the grease out of it and the hood as well. Be sure to wear rubber gloves when using the super clean, it's in the automotive section if yo have a spray bottle you can buy the gallon jug it's like $7.00 for a gallon and $4.99 for 10 oz. spray bottle and I use it on everything cars stoves washing machines and any appliance that needs cleaned it is a very powerful cleaner. Hope this helps, if this does not do the trick let me know and I will give ya some more advice but pretty sure it's just the spattered grease holding it in place. Hope this helps and thanks for using fix-ya.