Cats Ruined Mattress

Is there a way to clean my mattress if my cats had soiled my bed with pee and poo before they were fixed . I just got home from school and my cousin told me they peed and pooped on my bed and no one cleaned it so it kinda soaked through the mattress and i tried putting baking soda and the miracle nature but it still smells like poo. Will I need to buy a new mattress or can I fix this issue?

The cats are 1 years old. And we are from America (CA). And both cats were males.