Besides mentally offering the food before you eat it, it also helps to physically offer a small portion of the food. For this purpose, you can keep a small bowl or plate that has never been used for anything else. If you're really gung-ho, you can get a ser-kyem offering set and use that, with liquids going in the top bowl and solids going in the bottom bowl. After the meal, the food can be taken outside and left for animals to eat or, if that's not possible, it can be thrown away. Similarly, at a restaurant, you can put a small portion of each dish on a butter dish. In that case, the food just gets left there when you finish. No need to carry it away with you. Bottom line, keep it simple and workable. If it's not possible to make a physical offering, then, as Malcolm suggests, just do it mentally. As I'm sure Malcolm will agree, the mental offering is the more important of the two. Without the mental offering, the physical offering is not very meaningful. However, combining both is really good if you can manage it.