Mix 1/2 quart of warm water, a squirt of dishwashing detergent and 1/2 tablespoon of ammonia in a spray bottle. This cleaning solution, according to University of Illinois, is effective in removing red food coloring.
Spray the cleaning solution on the stain lightly. Do not saturate the mattress pad inside. After 15 minutes, blot the stain with a dry rag until the red coloring no longer transfers to the rag.
Moisten the stain again with the same cleaning solution. Wait 15 minutes and blot.
Spray any remaining stain lightly with a solution made with 1/2 tablespoon of white vinegar and 1/2 quart of warm water. After 30 minutes, blot the area with a dry rag. Let the mattress dry completely before putting your sheets and blankets.
Set up fans and open windows to air dry the mattress before you put on the sheets. If it is winter, turn up the heat in the room, if possible, to speed up the drying process.