DROPALL help:

dropall [type]

dropall drops all items in your inventory to the ground, excepting
locked items.  The type parameter will also control what is dropped:

'empty' (eg, nothing speciified) - drops all objects except food, money, keys,
  and containers.
weapons - drops weapons, bows, and arrows.
armor (armour) - drops armor, shield, and helmets.
misc - drops horns, books, girdles, amulets, rings, cloaks, boots, gloves,
   bracers, scrolls, wands, rods, and potions.

See also 'drop' and mouse button control for dropping objects.