How do I get mold out of my memory foam mattress topper?

Asked by rory (1407) August 29th, 2016 from iPhone

I have a three inch thick memory foam mattress topper that I use on top of my my dorm mattress at college every year. I’ve had it for 3 years and have kept it in storage for the summer in past summers. After storage it’s always smelled a bit odd, but usually returned to normal after a couple days. This summer I decided to lend it to my friend, who was living in a basement. The basement was very damp and had no windows. My friend ran a dehumidifier in the room every night, but now that I’ve gotten my mattress topper back, it smells like mildew. the smell isn’t overpowering, but I can smell it in bed through my sheets and mattress pad. I’m wondering how I can get the mold/smell out. It was expensive and I only need it for another year so I’d like to keep it if possible.