Vacuum the crib mattress to remove light dust and buildup. Remember to vacuum along the seams where dirt often sticks.
Mix 1 gallon warm water, 1 cup vinegar and 1/4 cup laundry detergent in a cleaning bucket.
Dip a soft brush in the solution, and scrub gently over the crib mattress. Continue until you have cleaned an entire side of the mattress.
Rinse a cleaning rag with warm water only, wring out and wipe over the side of the mattress that you have just cleaned.
Repeat this procedure on the opposite side of the mattress as well as along the side seams.
Sit the crib mattress in direct sunlight, when possible, and allow to fully air dry before using the mattress.