I’m doing some of the rebuilding of an old Mill House we bought in November last year, leaving structural stuff to the experts.
The landing/bathroom floor in the oldest part of the house is elm boards up to 14 or 15 inches wide. Unfortunately the previous owners kept 15-20 dogs there, not house-trained, so the boards are soaked with dog urine as well as being badly damaged on the edges and upper surface by woodworm.
We’d like to keep the boards if it’s possible to get them looking good, and to get rid of the smell.
I’ve lifted the boards (to replace the elm joists) and experimented with one of them, taking about 30mm off the edges and sanding a bit of the surface with a 4″ belt sander. I also flipped the board over and sanded a section of the underside.
I now think I’ll have to take the edges off all the boards and about 4 or 5mm off the original surface to get rid of most of the urine-soaked wood, then use the underside as the new finished surface, taking around 2mm off this as well.

My first question is how to do this. I spoke to a local hardwood timber supplier who could process boards up to 12″ wide with their planer-thicknesser but if there are any nails – even small panel pins, of which I found several with the belt sander – it’ll cost me £100 plus 3/4 hour labour charge per strike for blade replacement. So, I don’t think that’s viable. Using the belt sander also isn’t an option: even with the coarsest grit belts, it would take far too long to take that much wood off.
So, I’m wondering whether a floor sander will do this, and shrug off very small panel pins..?
Alternatively, would I be better off spending the hire cost on a cheap electric planer and some spare blades, knowing that I’d probably write the machine off doing this job? Any recommendations?

Second question: has anyone had a similar problem and cured the smell by treating the boards with chemicals? So far, I’ve read recommendations for vinegar, sodium bicarbonate, hydrogen peroxide and lime… Of those, I’m considering trying lime, as limed elm boards might be attractive anyway, but I’d be happy to hear if anyone’s had any success with this or any other method…