Remove the sheets and mattress pad if one is covering the pillow top. Fill the spray bottle with the distilled white vinegar and spray the vinegar on top of the stain. Allow the vinegar to sit on the stain for 5 minutes.
Shake the box of baking soda over the stain so the baking soda coats the stain and vinegar. The combination of baking soda and vinegar will cause fizzing. Once the fizzing has ended use a cloth to soak up some of the vinegar. Use a vacuum cleaner with upholstery attachment to remove the baking soda. If the stain is still present, proceed to Step 3.
Wet a cloth and rub it over the stain. Pour a small amount of Borax onto the wet stain. Rub the area in a circular motion with the cloth for a few minutes. Wipe down until dry and vacuum when dry.
Take hydrogen peroxide and apply it to a cloth if the stain is still visible. Dab the stain with this cloth for a minute or two. Note that peroxide can cause bleaching, so test it out on a corner of the mattress first.
Spray the stain with pet cleaner that contains enzymes and let the solution sit on the stain for 15 minutes as a last resort. After 15 minutes use a clean cloth to wipe off the cleaner and dry the area. When it is dried, run the vacuum cleaner over it.