Nice to see you back recently, Euripides. I'd been missing you.
Pentacles can be Earth if you envision them as carved from stone or metal. Or Fire, if you see the metal as smelted from ore and forged in fire. Or as Air, if you see it as a pure thought-symbol, or a piece of jewellery with holes that will let air through. Or Water, if you see it as painted on a pebble and dropped into a stream.
Cups can be Water, if they are filled with water. Air, if they are empty. Fire if they are filled with a flammable liquid (like, say, brandy or rum). Earth, if they are modelled in clay, or metal-mined-from-earth, or even glass, which is made of sand.
Swords can be Earth, because that's where metal comes from. Water, because they spend a part of their life-cycle molten, and can draw liquids like blood. Air, because of sharpness of thought, and being streamlined in flight. And Fire, because of being forged in a furnace.
Wands can be Earth, because wood grows from soil. Water, because trees need water to grow. Air, because trees need Air to grow, and wind blows between tehir leaves. And Fire, because they need sunlight to grow, and they can burn.
See? You *can* stretch things too far, if you're of-a-mind.