To care for your Casper Duvet, machine wash in a large front-load machine in cold water on a gentle cycle. Then, tumble dry low with dryer balls (or clean tennis balls). Before removing it from the dryer, ensure the duvet is completely dry before putting it back into the Duvet Cover.
Do not iron or dry clean the Duvet, as certain chemicals can dry out the down clusters and cause them to break down faster and lose their resiliency and insulation properties. During use and wash/dry cycles, feather bits may come through the shell - this is normal. It's rare for full-down clusters to come through the shell.