Okay, long story short, I live with my dad because he can’t live by himself. I’m planning on having company over later this month, and the couch basically smells a bit nasty because he sits on it all the time and sweats (it’s always very hot in our apartment). There are no stains to speak of, just a mild odor. But if someone’s going to be sleeping on it, I’d prefer that odor not be there.
I’ve tried Febreze, but it only covers up the smell for a day or so. Suggestions?
The rental carpet cleaners at the grocery store can be rented with an upholstery nozzle. That’s what I’d use.
Best way I know of is to get it some air. Get it outside for a while if possible? Of course for it to really air it would take a few days, I’d imagine…
“Borrow” a couch from a hotel or apartment lobby.
Call a pro. That is, call one of the many professional cleaning services in your yellow pages. They’ll come right out and steam-clean all the stink demons out of that couch with high-dollar equipment better than anything you’d care to purchase yourself, and it’ll only set you back a few bucks.
Ditto on the pros. Also, if you can afford it, a slip cover will help. And hit it up wit Febreeze shortly before your guests arrive.
I suggest febreeze it like none else just before your guest get there. Then (and this is the most important part) the next day, after they’ve slept on it, ask them what they did to the couch cause now it has a weird smell.

I’ve got one of those Bissell extraction machines which sprays diluted soap onto the upholstery and sucks the stanky out. It has worked quite well on second hand furniture, as well as car interiors.
I work for La-Z-Boy furniture here in central Florida. Chances are, the funk is in the foam or stuffing. If the cushions are detachable and you can open them up; take the foam or filling out at let it air out in a dark cool place for a few days. Wash the cushion covers. Steam clean the rest. If all else fails after that, then I can reccomend a nice new sofa for you. 