Being a beauty therapist I know how damaging these tools can be for the skin, but I love mine lol.
I use it on my nose round the sides and just in the are between my chin and lips.
No matter how much I give my face a good scrub I do still have residue of old make up and moisturiser in the pores around my nose and this tool really helps me get it all out.
I push down and slowly drag along my pores and all the gunk comes out, but not too hard as you can bruise or even take a little bit of skin off, just imagine its like an exfoliator you don't need much pressure to get your desired results
It is also fantastic for getting out ingrown hairs, use the sharp end to slightly scratch the skin so you can get the hair out from being trapped under the skin, then use the other end to help push out all the stuff in the hair follicle.
Make sure to spray with Isopropyl Alcohol to keep bugs at bay.
I purchased one of these after seeing it used on a friend and a beauty spa place overseas and being rather intrigued.
I find it does work well at getting out blackheads and the like that are fully developed but it can be a bit dangerous for someone like me who doesn't know when to stop. It's not pain free and I have ended up scratching my delicate skin with it so I don't use it as much anymore. It is easy enough to use you just have to be as gentle as possible with it in my experience. Because of this think it is more suitable for those with blemishes that are more on the surface than deep in the pores.