The home we recently purchased has urine stains on the hardwoods, which had been covered in carpet. We know that the previous owners had a dog. When I search the web for remedies, most of the suggestions are to sand and then re-stain the floors. There appear to be very few "cleaning" methods for removing the stains.

Is the conventional wisdom that cleaning just won't work? I'd rather not waste time messing around with cleaning products if the prevailing opinion is that they won't work.