The present invention relates to a mixture including at least O,O-tert-butyl-O-(2-ethylhexyl) monoperoxycarbonate and at least O,O-tert-amyl-O-2-ethylhexyl monoperoxycarbonate, where the O,O-tert-amyl-O-2-ethylhexyl monoperoxycarbonate is present in the mixture in an amount of from 0.001% to 45% by weight relative to the total weight of the mixture. The invention also relates to a crosslinkable composition that includes such a peroxide mixture and an elastomer; and to uses of the crosslinkable composition and mixture.