Turn away if you don't like mentions of a medical nature. I've had a seborrhoeic wart, which is the raised crusty version of an old age spot, as far as I can ascertain from internet research. Obviously it makes sense to have any growth or spot investigated by your doctor if you are worried.
However, the conventional wisdom is that freezing or surgery are the only options if you want a seborrhoeic wart removed, but with the magic of the internet I found someone who said theirs had disappeared with the application of tea tree oil to the wart.
I've been doing this the last few days, and it is definitely disappearing. I will embed the youtube below, and report back on my own progress in a few days, but it is another example of can't-hurt-might-help medicine which I think should be more widely disseminated lest people with these things resort to surgery without trying the simpler remedy.