How to delete all the inbox or archived messages in facebook?

Using GOOGLE CHROME 

• Go to SETTINGS
  

• Then on the upper left side click on EXTENSIONS
  

• Then at the bottom click on GET MORE EXTENSIONS
  

• Then on the top left side there's a SEARCH BAR write FACEBOOK DELETE ALL MESSAGES
  

• Then click on the + to ADD EXTENSION ....Then close GOOGLE CHROME
  

• Then re-open google chrome go to facebook click on the MESSAGE ICON and then See All
  

• Just click on THE FACEBOOK DELETE EXTENSION ICON  and click launch
   

• if u have any messages in OTHER or ARCHIVE put them all in INBOX and this EXTENSION will delete all of those inbox messages.