Don’t leave items or Gold lying on the ground any longer than necessary. Regular items (organ , white item , open socket item ) and Gold disappear in about 8-10 minutes. Magic items will disappear after 15-20 minutes. Rare, Set, and Unique items disappear after lying on the ground for about 25-30 minutes. for more info check-http://classic.battle.net/diablo2exp/items/basics.shtml