elf Makeup Remover Pen for $3 at Target (Amazon is linked here because Target doesn't list them online), I had to give it a try.
The pen is the perfect tool for fixing mistakes. It's precise enough to rub away rouge mascara without taking all the eye makeup around it. It also helped clear those last bits of eyeliner I can never remove with regular eye makeup remover. The tip stains easily (wipe it off after use), but that doesn't seem to alter the performance. At least, it hasn't yet. It doesn't leave a residue either so you can go right back to applying makeup after you use it.
This product is really meant for small scale use. The package even says so. Don't try to use is as a primary eye makeup remover. It isn't made for that. Also, it is rather stiff and scratchy so you don't want to do a lot of hard rubbing. This isn't a felt tip marker. It is more like a stiff permanent marker.
It's a great tool to throw in your makeup bag, and it won't cost much, either.