Help! How remove cat urine odors from wood furniture?

My neighbors bought only wood furniture and put it in the biggest bedroom of the guest house. Guest house after reconstruction and there is everywhere new tiles floor and no any other furniture yet. The only they bring there new: 7 feet H x 14 feet W wood cabinets (it made with 4 pieces). 2 Middle sections are with doors at the bottom, but 2 at the sides are just opened and it looks like smell comes from bottoms of last shelves at both sides. Maybe people kept cats litter boxes on that shelves or next to shelves or maybe cats just marked these parts...
I talk to my neighbors and they said that ordered special lamp to check where these spots are and will try to used everything what they found in the stores today, already ordered online include everything what members of this forum told me about.
Also they said, that if they already got this problem, they will try each way of cleaning separately, see the result and then will send this information online for other people. And of course they will stay in touch with me and I will post here all results about different procedures.

 

Black light.
Still have to kill what you find.
You can use a big box outside like a washer/dryer or refrigerator one.
You can set up a tented area too.

 

A big box?....Smaller piece / section of furniture: 7 feet H & 2.5 feet wide with build in shelves.... They want to check with Black light for exact spots and then check again after each cleaning process.

 

If you were to ozone it.
Tent better for this but good luck!