This is my latest obsession in what concerns to nails. Coolest nails EVER.
Stop thinking about weird techniques such as scraping the polish or whatever you're thinking about.
What makes nails look so amazing is a polish called crack nail polish (you can find it in any colour but the one I like most is this black); but the best fact is that the use of it has no mystery!
The first thing is to apply a normal nail polish, any colour you like. Let it dry and then apply this crack nail polish on. As it gets dry you will see the effect. I think it's incredible and a progress in chemistry (just joking). But really, I found this out some months ago, and after wondering how the hell this was done, I discovered that it was no more than a nail polish.
Where to get it: Well, I'm not kinda expert in store location and that's why I ordered this from the net. I'm sure there are many shops where this crack polish is sold but I'm sorry for not having the answer.
Mine's brand is called O·P·I (yes, like that Family Guy's sick man); it's really affordable but anyway, you can order it in ebay.com and those kind of cheap sites.
Hope you like this nails, post and who knows what else, but hope you like it !