Recently, conservators noticed frass—evidence of carpet beetles—emerging from the vehicle’s tan leather seats. The infestation presented a challenge: The seats, reupholstered using horsehair padding and leather, are structurally attached to the car’s frame, making a full interior inspection impossible. “There’s a small hole in one corner, but we don’t know if the extent of the infestation is causing a lot of damage and we’re just not seeing it yet,” she said. With little published guidance on pest eradication for oversized objects and the material complexity of a car, Anna-Colette reached out to conservators who had faced similar situations and built a full decision matrix to weigh her options. “The normal pathway in most museums is to  freeze items,” she said. After ruling out industrial freezer rental as impractical, she identified two viable roads to explore.

This summer, after removing the convertible top, she and Winterthur conservators will seal the car’s upholstery inside black polyethylene bags, creating a microclimate that absorbs heat from the summer sun. Bluetooth temperature and humidity monitors will track conditions as the interior gradually reaches about 120 degrees Fahrenheit—warm enough to kill pests without damaging the leather, paint or other historic materials. If signs of infestation persist, she’s recommending the entire vehicle be sealed inside a bubble and oxygen-scavenging packets be deployed to eliminate any remaining pests.

Because the Rolls-Royce could face future infestations, Anna-Colette is writing an instructional guide so Winterthur’s preventive conservation team can repeat the protocol if needed. “There are so many applications where something like this would need to be known,” she said, “not just in the context of a car.”