How to get Vim to highlight non-ascii characters?

Question

I\'m trying to get Vim to highlight non-ASCII characters. Is there an available setting, regex search pattern, or plugin to do so?

Answer 1

Somehow none of the above answers worked for me.

So I used :1,$ s/[^0-9a-zA-Z,-_\.]//g

It keeps most of the characters I am interested in.