To warm up just your egg whites or egg yolks, separate the eggs when cold and place the whites and yolks in small bowls. Place these bowls into slightly larger bowls full of warm water and allow them to sit for 5-10 minutes (or simply let them sit, covered, at room temperature for 30-60 minutes before using).Leftover egg whites or egg yolks can be stored for later use.lace these bowls into slightly larger bowls full of warm water and allow them to sit for 5-10 minutes (or simply let them sit, covered, at room temperature for 30-60 minutes before using). Leftover egg whites or egg yolks can be stored for later use.