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The Carl Zeiss Foundation of Mainz, Germany, has a new way to recycle old
lenses (GB 2359768). Crushing optical glass between metal rollers contaminates
it with tiny particles of metal, spoiling its optical properties. So Zeiss
proposes crushing the glass without contact. Waste glass on a conveyor moves
past sharply pointed carbon-fibre electrodes which are bathed in powerful
microwaves. The microwaves induce a current in the electrodes, producing sparks
and hot plasma at the tips. This shatters the glass into tiny pieces.