I have a 8 year old dark green couch that is covered in a really hard wearing chenille fabric (so I anticipate having this furniture for a long time). My dog always lays on the floor and leans against the side of the furniture. There was a sort of light whitish "haze" on the lower part of the couch from the oils in the dogs coat. It also makes the whole room smell "doggy". I have had the couch professionally cleaned. It is very expensive and doesn't last for long because she always lays in the same 2 spots right up against the furniture again (The professional cleaner said this is very common thing for dogs to do).
It was hot and humid yesterday so I had the windows closed and we used the air conditioning for the first time this summer. I really noticed the doggy smell with the windows closed so I knew I had to do something about it. A friend had mentioned that she has used Windex on her upholstered furniture to remove oil/odour from her dog. I checked the Windex bottle and it does say it cuts grease. I diluted the Windex with water and used a cloth to rub the soiled areas. It worked like magic! It removed the "haze" and left a really, really light Windex scent (instead of doggy odour). I wish I had thought to take before pictures.
Now I probably should have tested this in an inconspicuous spot but sometimes I just tend to dive right into things and my couch fabric has proved to be pretty sturdy stuff. The Windex didn't seem to bother the fabric. It didn't cause fading or anything like that. I will totally try this again and maybe experiment a bit with something a little more environmentally friendly like vinegar. Now if I can only find a way to get the dog hair off the couch!