You should be able to remove it from the hood. Ours just pops out. Sometimes they slide out. Soak in warm soapy water and rinse and wipe off. If they are especially dirty, let it soak longer, rinse, repeat as needed. If you do not know how to get it down, you might google the company name of the stove and find out how to care for the filter. They may have an explanation how to remove yours. Hope this helps Lyn.
Put them in the dish washer.
I wold remove it and soak it in very warm water and a dish soap, like Dawn, which are specifically designed to work on grease. If it’s really bad you could scrub it with a very soft brush; a toothbrush for example. Some are even top-rack dishwasher safe.
Get a good sized container and add warm water to it, put some blue dawn dishsoap, and add a little vinegar, take out your hood filter and put it in the soapy water. Let set for 10 to 15 min, take it out rinse off and dry.
Soak in hot water and a good grease cutting soap like Dawn. Rinse well. If dishwasher safe it can go in there too.
Take it out soak it in degreaser and hot water then rinse it out let dry and put back