When fragrances get cold, some of the components can get cold and freeze, just like ice. This can make the fragrance appear cloudy or even have hard crystals throughout it. Simply heat the fragrance up slowly in a double boiler, with the lid off, until the ice-like chunks disappear. Place the lid on your fragrance and shake well. You can heat the fragrance up in the microwave, without the lid on, on short 20-second bursts as well.