How do you keep mattresses fresh between home exchanges?

For hosts preparing their homes between exchanges, what are your preferred ways to keep mattresses fresh and hygienic? I’ve been looking into mattress steam cleaning Brisbane options and came across Austech Carpet Cleaning while researching local cleaning methods. For those who use mattress steam cleaning Brisbane, what has worked well for removing odours, dust, and everyday buildup?

I just use a waterproof mattress cover and a normal one over it.