Dear Mary: I found a great deal on a gorgeous couch at an estate sale. It is upholstered in white leather and appears to be new—as if no one has ever sat on it. Priced at $100, you can be sure that I grabbed it up fast and brought it home. I put it in the garage. Then it hit me—the reeking smell of old, nasty cigarette smoke. Once I closed the garage door, that smell almost knocked me over. I just didn’t notice this at the sale. I’ve done a little research on how to rid leather of cigarette odors. Some say to wash it down with vinegar and allow it to dry. Others say no, that will damage the leather. Do you think that Nok-Out, the odor eliminator you often recommend, would work without harming the leather? I’m so bummed. It is a beautiful couch and very much …