Strip the bed and remove all bedding
Vacuum the mattress surface thoroughly, including seams and edges
Spot-treat stains with a mattress-safe cleaner
Blot stains with a clean cloth; do not soak the mattress
Sprinkle baking soda evenly over the entire surface
Let the baking soda sit for several hours
Vacuum the baking soda off completely
Flip or rotate the mattress if recommended by the manufacturer
Clean the mattress sides and underside if accessible
Allow the mattress to air out and dry fully
Use a fan or open windows to speed drying
Refit with clean, dry bedding only after the mattress is completely dry