When I made my brow routine post a few months ago, someone told me that they use Permanent Taupe on their eyebrows. Curiosity got the better of me a few weeks ago and I finally tried it out. I was dubious that it would be a little too pale for me, but it is a great colour! It is similar in shade to Mac's Charcoal Brown Eyeshadow which I normally use, but a tad more grey toned.
I run a spoolie through my brows then apply this in little strokes with an angled brush, shaping the front a little as I always do. The spoolie goes through again and Benefit's Gimme Brow Gel in Light/Medium follows to add a little more dimension and hold - and voila!
Have you found any products that have unintended uses?