Claws

The cats claws picture is courtesy of A.Vale

When cats are scratching things in the house with their sharp claws, they do it for satisfying their urge to stretch themselves after all this long hours of sleep…
They scratch to clean and strengthen their claws, and also to mark their territory.
I have read somewhere that the scratching is not for sharpening the claws. Need to check it out. If anyone knows, how do cats keep their claws so sharp all the time? Leave your comment!