It's a good wood stain. It was often used to stain boxwood instruments dark brown (recorders, clarinets, flutes, bagpipes). If you have a darkened boxwood instrument the chances are you're inserting something in your mouth that has been left to soak in pre-antibiotic-era pee for several weeks.

There are of course hundreds of Gaelic songs to accompany pummeling urine-soaked tweed on a table.

Inteh 18th century, a dyeing process was dicovered that used a mixture of urine and a specific seaweed from the west coast of Scotland to produce a strong blue colour. It was done in a factory in Glasgow, under conditions of the greatest secrecy to preserve the inventor's monopoly on the process (the factory had high walls and all the workers were monoglot Gaelic speakers). The urine was collected from the East End of Glasgow. But once the locals figured there was money in it, the urine collectors had to carry hydrometers - the suppliers were watering it down.