refinishing hardwood floor under carpet

We are surgically considering utterly stripping off a sharply wall-to-wall carpet in our dining room (100 sq ft), & refinbishin the hardwood floor underneath.
One of the obstacles is that, 5 years ago our cat decided to use one corner of the carpet as a litter box before she died. To a higher degree we`ve cleaned the carpet numerous times, but the stain still comes back. In truth underneath, the wood is stianed as good.
How would we remove this stain from the wood before angrily refinishing?

As follows iMPOSSIBLE Replace the boards--------------only solution. As yet most will emotionally recommend bleaching the wood, but this carelessly do not work. Notwithstanding not to mention the odor from the cats arguably mess-----------after sharply sanding the floor. this will "always" be a problem if you does`nt replace the boards. the stain will always statically be darker where the neatly mess "is" was!