Before you grab an insecticide and douse the beehive, take the time to prepare for the complete process. This is especially important if the hive is built into or onto your house. You should:  Prepare to do repairs following the removal of a large honey bee hive from a home. Walls or structure may need to be cut away to gain access. Plan to bee-proof to avoid further infestation in areas where the hive and honey can't be removed (for instance, behind stucco and brick). Consider evacuating those with allergies, children, pets, and the elderly from the immediate area where a hive is active. Bees are normally asleep (and thus in the hive) in the late evening and early morning, so these are the best times to spray the hive. In terms of seasons, the best time to remove a beehive is late winter to early spring. During this time the beehive population is smallest. Bees are less active at night, and will likely all be at the hive then. However, it's harder to see and effectively kill bees at night. If you do want to spray at night, use a flashlight with red cellophane covering it—bees can’t see red light. Dress appropriately for exterminating a beehive. Clothing is a very important part in the process of removing beehives. Light colored clothing with a smooth texture is best for removing bees. Dark colors and rough clothing are more likely to agitate bees.  Choose heavyweight clothing that covers your arms and legs. You may want to invest in a white beekeeper’s suit. Wear gloves that offer substantial protection for your hands. Professionals usually prefer leather gloves when removing beehives. Professionals use a beekeeper's veil, which offers great protection while not hindering your vision. Buy one online or at an agricultural supply store. Don’t wear heavy scents like perfume, cologne, or scented deodorant. The bees may confuse your scent for that of flowers. While you can find homemade recipes for eradicating beehives online, your best bet is to use a commercial insecticide. Go to a home center and pick out an insecticide spray that is marketed for use on bees. Instead of a spray, you can instead buy an insecticide dusting powder. The application process will be quite similar regardless. All beehives have a main entry hole that is usually easy to locate. Hold the nozzle of the spray can right up to the opening and spray for several seconds, until you estimate that you’ve saturated the entire hive interior.  If you’re using an insecticide dust, stick the tip of the applicator into the hole and squeeze the bottle to inject the dust into the hive. If you can’t find or can’t access the main entry hole, spray the insecticide all over the outside of the hive. This will do the job eventually, but it will likely take several more spraying applications over a few days. Check the hive the day after spraying it. If you don’t see any bees enter or exit over a period of 5-10 minutes, the hive is almost certainly eradicated. Otherwise, spray your chosen insecticide into the hole again and check the following day for activity. Don’t start removing the hive until all the bees are dead. Otherwise, they’ll become very aggressive when you tear into their home! Also, if you’re unable to remove the entire hive, any remaining bees may be able to rebuild it.

Summary:
Plan ahead for the extermination, hive removal, and any home repairs. Wait for late evening or early morning, and (ideally) late winter. Put on protective gear like long sleeves, gloves, and a bee veil. Choose an insecticide that’s intended for killing bees. Spray the insecticide right into the main entry hole of the beehive. Repeat the process daily until there’s no more hive activity.