Supplies you need:

a cup of baking soda
four to five drops of lavender oil (or other essential oil you prefer)
a jar with lid
a vacuum

Combine the ingredients in a sealed jar and shake well. Sift the mix over the mattress (Above mix can cover half of a King Bed). Leave for an hour in order to give time to the ingredients of the mixture to draw out the dirt and moisture. Then vacuum it clean. Lavender oil is great choice for sleep promotion and stress release, you can use tea tree oil or other essential oil you love.

How to Clean Mattress with Baking Soda video

—- More DIY Ideas —-

Clean My Space‘s Melissa Maker can lend a hand. Her 10-minute “How to Clean Your Mattress!” video is thorough and covers dry and wet options, as well as advising you when to call in the professionals. To get the full Maker treatment on the subject, click on the video below.

Here are a few of her tips:

It is best to vacuum every time you rotate your mattress, or once a season. The key: “use a clean upholstery attachment” since the vacuum has, well, a dirty job.
Deodorize the mattress by sifting baking soda over it, let it sit for 30 minutes and then vacuum it up with the clean upholstery attachment.
If you need to tackle stains, the main three are protein, grease and tannin, with protein being the ones you see on the mattress.

One Good Thing shares the good article on how to clean your mattress with baking soda as well: