Particulate bleach activators comprising 15 to 60% by weight of an acetonitrile, 20 to 70% by weight of a silicon-containing carrier material and 20 to 30% by weight of water, which are obtained by applying an aqueous solution, saturated at 10 to 40° C., of an acetonitrile onto the carrier material without subsequent drying, where the amount of saturated aqueous solution is measured such that the given limits for acetonitrile, carrier material and water are observed.