Housebreaking an Older Dog

Housebreaking an older dog is not an impossible task. Although it is generally easier to housebreak a puppy, any dog can be housebroken given the proper techniques. First, before you begin, you must know how a dog thinks. I would say that a dog thinks 80% of the time with its nose, and the rest of the time with its other senses. If you look at animals in the wild, you'll notice that most mammals like Wolves, Lions, Tigers, and Wild Dogs scent mark their territories. This is not only a sign of demarcation, but a place where these animals return to mark over and over again, in order warn other animals or their rivals that this is their territory.
It is precisely this habit that the distant cousins of wolves, our dogs, exercise on a daily basis. That is, dogs know and remember where to go "potty" by mainly using their sense of smell. Dogs a creatures of habit; therefore, they generally like to go "potty" after a meal, after they wake-up from a nap, and after they exercise. Your job is to recognize when your dog needs to "go" and guide it to the pre-designated area before it does its business. Thus, you must monitor your dog for at least 2 weeks until the desired outcome is programmed into your dog's psyche.
So, what are you to do if your dog makes a mistake and "goes" in the middle of your living room? The answer depends on whether you catch your dog in the middle of the act or not. If you catch it in the middle of the act, you can say something like "no," and quickly lead your dog to the desired location before it finishes doing its business. If, however, you find the mess after the fact, you must NEVER punish your dog. Your dog simply won't understand what it is being punished for and it will soon learn to fear you instead of look at you as its leader.
The question then is "what should one do if one finds the mess after the fact?" My advice is as follows: take a newspaper or towel and rub it onto the mess; then, take it back to the location where you desire your dog to "potty," and smear that area. This will teach your dog to use its natural instincts (to scent mark) to go "potty" exactly where you want it to. But you still are not done yet! Now you must erase your dog's memory of the location in your house where it had gone "potty" by properly cleaning the spot with the right cleaning agent. Cleaning with ordinary household cleaners is a bad idea. Most household cleaners contain Ammonia; the very ingredient in Urine which arouses a dog's instinct to scent mark. So, instead of using ordinary household cleaners, use a product like "Nature's Miracle," which is specifically designed to remove the smell of urine and feces and erase you dog's memory of the previous location where it had done its business.
The key to housebreaking an older dog is patience. Be patient, and you dog will learn to do what you ask of it in no time.