In a prosecution for a violation of Penal Code section 4502, possession or manufacture of a weapon in a prison, the trial court did not err in refusing to give CALJIC 12.06, temporary possession for purposes of disposal. Here the court held necessity did not require that appellant possess the weapon, a blade fashioned from a disposable shaving razor. According to the court, rather than picking it up himself, appellant could have notified a guard that it was lying on the ground.