What is the best way to remove a musty smell from a mattress?

Long story, but recently or family cat became ill and died. While ill, it soiled my mattress. After trying some specialty chemical cleaners for pet stains, I decided I would make a last ditch effort to wash the mattress with clean water in my garage before resorting to trashing it….it was an expensive mattress.

After I rinsed out the mattress, I removed all the exess water with a shop vac, but the weather got really humid and it took a few days for the remaining water to dry out. In the meantime, the mattress took on a mildew/musty smell.

Is the mattress a lost cause? or is there a way to eliminate the mildew smell? It is very slight, but obviously any odor in a mattress is undesireable. For what it’s worth, the cat stain and odor is no longer present.

The mattress has been airing out in the garage with a fan for the last 6 days, and each day the odor is less…but is there a way to eliminate it?