I pulled off my sheets to wash them and noticed the mattress was no longer white. It was somewhere between beige and light brown, with a distinct darker outline of where my body goes. I had been sleeping on that thing for four years and had never cleaned it. Not once.

Mattresses are probably the most neglected surface in the house. We spend a third of our lives on them and almost nobody cleans them. Dead skin cells, sweat, dust mites — it all builds up. A typical mattress doubles in weight over eight years from accumulated debris. That fact made me clean mine the same day I learned it.

What you need

• Baking soda — a full box, maybe two for a king
• Vacuum with an upholstery attachment
• Spray bottle with cold water or diluted white vinegar
• Optional: a few drops of lavender essential oil

Step by step

1. Strip the bed. Wash all the bedding in hot water while you clean the mattress.
2. Vacuum the entire surface. Go slow. Use the upholstery attachment and do overlapping passes. Pay extra attention to seams and tufted areas where debris collects.
3. Spot-treat stains. Mix equal parts cold water and white vinegar in your spray bottle. Lightly mist any visible stains — sweat, urine, whatever — and blot with a clean cloth. Do not soak the mattress. Too much moisture leads to mold.
4. Cover with baking soda. Pour a generous layer across the entire surface. If you have lavender oil, add five to ten drops to the baking soda and mix it in first. The baking soda pulls out moisture and odor.
5. Let it sit. Minimum one hour. I do four hours when I have time. The longer it sits, the more odor and moisture it absorbs.
6. Vacuum again. Thoroughly. Every trace of baking soda needs to go. Empty the vacuum canister halfway through — baking soda fills it up fast.

How often should you do this

Twice a year is the standard recommendation. I aim for once per season change — when I switch from winter to summer bedding and back. It takes maybe thirty minutes of active work plus waiting time. If you have allergies, do it every three months. The dust mite reduction alone is worth it.

A mattress protector makes a huge difference going forward. The waterproof kind feels crinkly but there are quilted cotton ones now that do not sound like a potato chip bag. Worth the thirty dollars.