Sprinkle a layer of baking soda all over the mattress.
Leave for a few hours, then vacuum.
4 – CLEANING A MATTRESS WITH DISHWASHING LIQUID
Instructions
Mix 3 tablespoons of dishwashing liquid in 1 liter of hot water until homogeneous.
Application
Soak a sponge or washcloth in the mixture, wring thoroughly, and rub the mattress, covering all areas.
Rinse with a washcloth in clean water.
Press towels to absorb moisture and let air dry.