Real Simple offers advice on two methods, a long and a short version, and surprisingly neither seems out of the realm of do-ability even for a former mattress-care-slacker like myself. However, being nine months pregnant, I've decided to start small and go with the shortcut (slacker habits die hard).
Real Simple breaks the shortcut method into four easy steps:
1. Wash the mattress cover with 1 cup of white vinegar on the hottest possible setting recommended for your cover, soaking it in cold water with a cleaning boost agent like OxiClean first if it needs help with removing stains.
2. Sprinkle your bare mattress with baking soda using a sieve, distributing it evenly until it has a light dusting.
3. Put the newly washed mattress cover in the dryer with a few clean tennis balls to fluff it, or let it air dry outside.
4. Lay down a few dryer sheets with essential oil on the mattress (over the baking soda which you should vacuum up next time you make the bed), then remake the bed using the newly cleaned mattress cover and freshly washed sheets.
Check out Real Simple's full article for more details as well as for the long version.
I think I have my work cut out for me this Saturday morning.
Image: Real Simple