To skim means to read or review something quickly and superficially, often by glancing over it without reading every detail. It can also refer to a process where a thin layer of cream is separated from milk due to its lower density.
Usage examples
Skim the book to get an overview of its content.
Make sure to skim the milk before adding it to the recipe.
I like to skim the surface of the pool with a net to remove any debris.
It's important to skim the instructions before assembling the furniture.
Instead of skimming through just the new stuff (as is usually easier when we see a new blog) it is fun to really sit down and go through what else the blog has to offer. (angelaskitchen.com)