Does anyone have a Mac Powderpoint eyeliner, and if so, how do you sharpen it (or extend the tip in some other way)?

I bought one a month ago, and it's now blunt, but I can't figure out what to do with it. It has a plastic casing, so I'm nervous about taking to it with a sharpener.

Hope someone can help!

Just use a regular sharpener, it will be fine.