The pictures below are of a pine tongue and grove floor board removed from a house where the cats had used the area for a considerable length of time to relieve themselves. The board is discolored and damp from the enormous amount of urea salt on the surface of the wood. Observe below the "C" tag at the accumulation of material on the tongue of the board. There was another board placed tightly against this one and still this large accumulation occurred.
The board was cut in half at location "A" to expose the interior of the wood. Picture 2 shows the depth to which the urine has penetrated the wood (the wood is 3/4" thick).
Picture 3 and 4 are end views of section "B". Picture 4 is a close up of the groove area exposing the depth of penetration into the groove and the wood. Picture 3 exposes the overall penetration into the wood.
There is only one solution for contamination at this level. Replace the wood! There is simply no way that the contamination in this wood can be removed or neutralized in our life time. Treating the surface will not penetrate deep enough into the wood to prevent the urea salt in the board from migrating to the surface again and again. The area beneath this board and the ones adjacent was also contaminated but to a much lesser extent. So much less that after simple cleaning and several applications of OdorXit, the odor was eliminated.
The bottom line in this situation is similar to the old adage about Volkswagens: "Volkswagens will definitely float, but not indefinitely". There are limits to everything, and this is an example of a limit passed for OdorXit's ability to recover contaminated flooring material. The rest of the room was contaminated to a much lesser extent and was recovered. The rehabber in this case replaced the rest of the wood like this (about 16 square feet) with plywood and fastened it with construction screws, not nails (just in case).
Cats and Dogs, when confined as they apparently were in this case, will almost always use the same area to relieve themselves. Cats will almost always use a corner. Dogs, on the other hand, use the center of the area.