When you purchase lobsters, they most likely be be live, and you will put them directly into the steamer pot. But, if you have a leftover lobster tail from a restaurant or you purchased precooked lobster, you will need to reheat just the tails. If you put the tails into a steamer pot, the delicate meat in the tail could fall out since the lobster's shell likely will have been cracked. There is a better way to reheat lobster tails. Step 1 Preheat the oven to 350 degrees F. Step 2 Place each lobster tail on a single sheet of aluminum foil. Step 3 Sprinkle the water over the lobster tail. Step 4 Crimp the aluminum foil tightly around the lobster tail to form a closed pouch. Step 5 Place the aluminum pouch on a baking sheet and place it into the oven at 350 degrees for 18 minutes. Do not open the foil pouch before the time is finished. Serve hot with butter and lemon if desired.