I don't think you will be able to totally eliminate a smell so a dog can't smell it -- but if you want to eliminate smells and stains, "Spot Shot" is great. For odors (even old ones) "What Odor" is great. Google it.

As far as training an old dog, just put some of his poo in the spot in the yard where you want him to go. Should work -- he doesn't want to eliminate close to where he lives, so if he has a choice, he will get it away from his home. Why is this old dog not house-broken?

It is absolutely not true that a dog doesnt want to eliminate close to where it lives, some dogs, especially those from puppy mills have become desensitized to the fact that they have to practically live in their their waste and it is these types of dogs from these types of environments which are very difficult to train.
Your best best to to treat the area soiled as best you can. Many dogs habituate to an area so once you get as much smell out, cover the area with something you can toos or clean. Carpet remnants on a tarp might help.
Next take that dog out as much as possible, when out as soon as the dog eliminates, praise it like it has just brought you a bag of hundred dollar bills, and dont forget, while the dog is in the act, give it a command, like pp outside. or whatever you choose. Dogs learn very quickly by rote and the more you do this the faster they can learn. Good luck.

Dog naturally does not want to eliminate in his den space, that is why crate training could be so successful from the start. It is more difficult if dog was neglected and forced to soil his crate...
I would think that you housebreak adult dog same way as you do young puppy. It is really important if you stick to a really tight schedule like taking out your dog every couple of hours or depending on the breed/ small dog small bladder capacity/ even more often. I would go as far as to say - take a week off vacation when you bring dog home and teach the right way you want things happen in the house. Don't deviate from the route- same door, same spot, same way- do it for about a week. Repeating a cue word during actual process is great help for the future. Keep the water on limited basis at least for the beginning couple of days- give him after eating, after runs but do not leave water all the time, take the water last time few hrs before going to sleep. Make sure your dog does do things outside, yes, it could be rain or snow but you plan to be determinate.
Remove your carpets in the house if possible at least for the time being, leave as many surfaces that could be easily cleaned or let the dog run only in the area where it could be easily cleaned. Pet stores do sell cleanser but it still does not eliminate smell completely at least for the dog- I can not smell anything of course.
you have not told us if the dog is soiling in the crate. If dog can keep his crate clean it is very easy to teach, just take your time and take the dog out, after he sleeps, eats, plays, starts running in the circles and sniffing the ground or couple of hours in the house.
Do not teach dog to go on the newspaper or doggie pads if you can avoid it.
If it is a senior dog you might run into incontinence or urinary trouble but that is something to discuss with your vet.

To answer your question, I use Simple Solution on an area of carpet to get the smell/stain out. It can take keeping it wet with the solution for a couple of days. This stuff uses enzymes to actually degrade/eat the poop or pee, and can totally remove any trace of blueberry stains on white cotton in a day or two of keeping it wet with solution.

I have also used the hydrogen peroxide/baking soda/dish soap recipe in the thread below on the Animal Debates forum.

As for potty training an adult dog, I know that it needs to be done with complete consistency like Mazer says. Our Bina lived her first 4 to 5 years in a hoarder's kennel that was overcrowded with 150 dogs. She learned to soil her cage there. We do not believe she was ever outside until she was rescued two weeks before we adopted her. My DF-in-L had a major medical crisis a few months after we got her. It made our house into a zoo! Her fear of the outdoors and fear of people, wind, birds, neighbors, squirrels... made going outside something she avoided. If we remembered to take her out regularly, she would poop or pee as soon as she got onto the grass off the patio. If we were not thinking about her, she was happy to do it anywhere in a hall. If the patio is snow-covered in winter, she will poop or pee on the patio snow. If we had been more consistent, she would have gotten potty trained much better than she is. I agree with Mazer that taking a week off work would help.

Here is a link that might be useful: Formula for getting cat urine out permanently

My dog is not an old dog but is an adult dog that will be 3 years old this month. While it has been implied that my dog must have been purchased from a puppy mill, quite the opposite is true. My pet comes from an extremely reputable and thoughtful breeder who breeds to better the breed and mates a sire and damn only every 2 years. She has an immaculate kennel of champion show dogs. In fact my pet was a show dog temporarily; however, she did not like being on a lead, so a decision was made to offer her to a loving, caring home rather than imposing show rules on her. Although the breederÂs dogs are very, very often brought into her home, they are returned to the kennel every evening. Thus, none of the dogs are house trained, in the sense that I define house training, that I am aware of.

I do appreciate the advice given. I am currently taking vacation from work and that is one of the reasons I asked for advice at this time. I have been taking her out at approximately the same time every day and to the same area; so far, there has been some limited success. I will definitely try the peroxide, baking soda, dish soap solution. Thanks to all of you.

First, to answer your question, I use Natures Miracle and OdorMute. Keep in mind that the breed dog you have also plays a part in how quickly they house train. Some of the smaller breeds take awhile to catch on!

I used to foster dogs and found all the adult dogs easy to house train. Now, I have to admit that at the time I used a doggie door and once they learned how to use the door I never had accidents in the house.

My current dog was an adult when I adopted him and he was very easy to train by taking him outside regularly (no dog door in this house), and by using lots of praise.
Be sure to use certain words when they go and soon you'll find your dog will go (or try to!) on command.
Also, stay alert and look for little signals that they need to go out. My little guy will pace sometimes, other times he may just stare at me. Usually, if I'm at the computer he comes up and touches my leg with his nose.

Good Luck.........

I've adopted only adult dogs for the last 12 years. Not to mention foster them. So I have a lot of experience in training adult dogs from all sorts of situations. While eliminating the urine/feces smells from the house will help, it doesn't get to the root of your dog's problem- she thinks it's OK to pee and poop in the house.

Besides taking her out during specific times, please tell us what else you are doing to train her. Is she in a crate? If so, how long? What kind of exercise does she get per day? How often is she walked outside? What happens when she urinates or defecates in the house while you are watching her? When you are not watching her? What training methods besides scheduled times to go out are you employing? When you take her outside, does she go potty or not? How long do you wait for her to potty before bringing her inside? What does she do outside-play, sniff, want to go back inside immediately, chase squirrels, etc?

The more information you can provide, the better we can help you.

While you should try to get the smells out, you are not doomed if you can't. I have a carpet that has seen its share of accidents over the years. I adopted a young adult beagle two years ago, who was not reliably housebroken when I got her. She is totally fine now. Of all the breeds, a beagle is one of the most scent driven dogs of all, so I KNOW she can smell what I couldn't completely remove.