Hang the comforter, such as on a clothes line or over a railing, so the wrinkles settle. It may take only three or four hours for most of the wrinkles to disappear.
Iron stubborn wrinkles using the low, synthetic setting on your iron. The care label likely says you can iron it on low. You may, though, want to use a pressing cloth between the iron and comforter to further protect the polyester from melting or burning.
Place the comforter in a large-capacity dryer and tumble it on the low or no-heat setting for approximately 10 minutes. After it stops tumbling, take it immediately out, fluff it up and lay it on your bed. You can also add a home dry-cleaning cloth to the dryer if you would like to dry clean it at home, following the directions on the label.