I bought yarn from a friend ages ago that had some cow hair mixed into the wool. I intended to make a pair of naalebound short socks from it, thinking that they would be slightly more water repellant than regular woolen socks. Unfortunately I miscalculated how much yarn I would need and was unable to finish the socks. I put them aside and thought that I should buy some more yarn to finish them and then I forgot all about them. When I finally got around to asking the seller had no more left of the yarn so I had to go for something else for the last bit of the socks. If one tries to look at the bright side of this I have not only finally finished the socks, but also used up a small ball of brown yarn that I have had for ages.