The decal particles would need to hold the ent pointer.The manual says not to change the particles skill_x-z I'd bet one is the Ent pointer. You did say you wanted to kill all the dexals. So it should just be a matter of running a clink looking for the ent pointer. But i see no reason this is better then using the ent pointer in ent_getdecal to kill all of them.

Or why not just limit the lifespan upon creation.