1. Visit Gmail –> Settings –> Filters –> Create New Filter.
2.Now you will see a dialog asking you to identify what kind of mails should be filtered out before it gets delivered to your inbox.
3.Well now just add in: spam in the "Has the Words" dialog, and press Create New Filer, now you might see a popup, just press OK.
4.Now your New Filter is created just choose the options what you would like to do with those emails.
5.Well you can do many things like forwarding those emails to some cyber expert free analysis by adding his address or if you want to delete it just tick the Delete It option and mark Also Apply this Filter.
6.Now your filter is created and every email you receive in your Spam Folder will be deleted automatically.