Use of bleach may discolor or damage the rubber material. Eventually, this can cause the rubber to fall apart. Both vinegar and bleach are effective at killing mold. Bleach kills mold faster, but may discolor or weaken the rubber.
Wherever you find rubber, don't clean it with vinegar. The acid can eat away at rubber just as it does natural stone, causing it to degrade. Instead, use soap and water or a solution of soap and baking soda.