In microwave processing, toluene is the preferred clearing agent.

• A. True
• B. False
• C. Xylene is preferred
• D. Water is preferred

Answer: (B)

The main idea is that the clearing step in tissue processing must effectively remove alcohol and be fully miscible with paraffin so infiltration can proceed smoothly, especially when accelerated by microwaves. In microwave processing, xylene (or a suitable substitute) is preferred because it clears efficiently and blends well with paraffin, allowing rapid transition from dehydration to infiltration under microwave conditions. Toluene is not the preferred choice because it clears more slowly and can be less reliable for rapid, uniform infiltration, and it poses greater toxicity concerns. Water cannot serve as a clearing agent since it does not dissolve or displace alcohol and is not compatible with paraffin infiltration. Therefore, the statement is false—the preferred clearing agent is xylene or a substitute, not toluene.