What special products should I bring home to Beijing?

To tell the truth, there are no specialties in Beijing. Roast duck is one of them, but it is ok to eat in the store. Even if it is vacuum packed, many of them are fake and the quality is not good. Preserved fruit used to be famous, but now almost no one eats it. Some snacks can be considered, but I'm afraid you won't be able to keep them well in hot weather because of the long journey. As for souvenirs of those scenic spots, buy as little as possible, which are especially expensive and of poor quality.