Be honest. Sometimes happened also to you to see a file that you edited a while ago with Vim, still showing that terribly annoying yellow highlight. And I'm sure you probably gave up, thinking that the time was going to remove it. Wrong! :P Here how to get rid of it:

1. open the file
2. press ESC
3. type :nohl
4. press Enter

Alternatively, the way I kept to use (which seems easier to remember), is actually search for some crazy string. For example:

1. open the file
2. press ESC
3. type /fkjsaddflkjasd;flka(randomly type stuffs)
4. press Enter

Done ;-)