[SCRIPT] destroying key after use?

[zombiehacker595]

how do my key after use
i have takin heeps out out of the script this is just the door opening door thingy
void OnStart()
{
AddUseItemCallback("OpenDoor", "key_study_1", "level_wood_1", "UnlockLevelDoor", true);

}
void OnEnter()
{
}
void OnLeave()
{
}
void UnlockLevelDoor(string &in item, string &in entity)
{
SetLevelDoorLocked(entity, false);
}
what would i have to add to destory the key after using it to unlock the door?