Back when I was at school, I couldn't go a day without using my eraser. That one magical thing that would fix all your mistakes.
I'm pretty sure, often enough, as you're doing your eyeliner, you mess up and it's pretty annoying to either have to clean it all, or correct if with Q-tips.
That's why when I decided to give Too cool art class, a try.
On one side of the pencil, you have a kind of transparent wax that you will have to apply over the lines you want to erase. As you use it up, you will have to sharpen it, which also helps when you want to erase precisely.
And on the other side, you have a sponge like end. You use this end to clean the eyeliner.
To be honest, I'm not a big fan of this sponge, as I always kind feel like it will break ... I tend to use a Q-tip if I have one at reach. I also find it quite hard to clean as well, as I really feel like it is very fragile.
Now concerning the power of the pencil !
I swatch Waterproof pencil eyeliner, liquid eyeliner, gel eyeliner and a waterproof mascara.
And here's how I erased half of the lines. It did a pretty good job on all the swatches without having to rub hardly on your skin, which you wouldn't like to do around your eyes. The lines are then clean, and ready to apply eyeliner over again.
I like the Too cool art class to correct my cat line whenever the flicks aren't even and also under my eyes when my mascara touches my skins as I apply it.
One of my must have in my purse, as you always need a quick fix ;)