To clean up a fresh stain on a mattress, sprinkle the stain with talcum powder and leave for a few hours. Vacuum the powder off. If there is still a stain remaining, dampen it with a cloth soaked in 1 part cloudy ammonia and 10 parts water.
If it is a blood stain, dampen the stain with cold salty water and dab with a sponge or damp cloth until the stain has gone.
Urine stains can be sponged with dishwashing liquid diluted with water, then rinse thoroughly.
A hairdryer is good for drying the damp spots. Make sure you keep drying for a long time after the damp area seems to be dry because it is likely to be damp underneath and that dampness won’t become noticeable until someone is sleeping on the mattress again. A child won’t notice any remaining dampness and yet that can cause colds and simliar illness later.