De-Comp Composites Inc. (Cleveland, Okla.) has developed Virtual Core, a "green" liquid that can be used to fill aluminum and polymer honeycomb structures in preparation for machining. The water-based product develops machinable properties when dried, allowing the core materials to be routed or cut as solid structures. The manufacturer says the material is water soluble and, therefore, can be removed easily after machining. The material is recoverable and can be recycled.