I spilled an entire cup of coffee on my mattress at 6 a.m. on a Tuesday. Not a little splash — the full mug. It soaked through the sheet, the mattress protector, and into the mattress itself. I stood there in my underwear staring at a brown stain spreading across $900 of memory foam.

That was the day I learned how to deep clean a mattress. Here is everything I figured out.

Start With the Baking Soda Treatment

Sprinkle a generous layer of baking soda over the entire mattress surface. Do not be shy — use at least a cup. Baking soda absorbs moisture, neutralizes odors, and helps lift stains from the fabric. Let it sit for at least an hour. Longer is better — I leave it for three to four hours when I can.

After the wait, vacuum it all up with the upholstery attachment. The baking soda will have pulled up moisture and smells you did not even know were there.

Spot Clean Stains With Hydrogen Peroxide

For fresh stains like my coffee disaster, blot immediately with a dry cloth — do not rub. Rubbing pushes the liquid deeper. Blotting lifts it out. Then mix equal parts hydrogen peroxide (3%) and cold water with a drop of dish soap. Dab the solution onto the stain with a clean white cloth. The peroxide breaks down organic stains without bleach or harsh chemicals.

For old stains, make a paste of baking soda and hydrogen peroxide. Spread it on the stain, let it dry completely (an hour or two), then vacuum off the powder.

Deodorize With White Vinegar Spray

Fill a spray bottle with equal parts white vinegar and water. Lightly mist the mattress surface — do not soak it. Vinegar kills bacteria and neutralizes odors as it evaporates. The vinegar smell fades within a few hours. Open a window or turn on a fan to speed up drying.

Protect Going Forward

After the mattress is fully dry — give it at least six hours, preferably overnight — put on a waterproof, zippered mattress encasement. Not just a fitted protector that goes over the top like a sheet. Get the kind that fully encloses the mattress with a zipper. It blocks dust mites, spills, and body oils from ever reaching the mattress again.

I spent $35 on one after my coffee incident. Best $35 I have spent on bedding.