Note: When troubleshooting Email Purging, Purge the Trash after successfully purging Inbox!
Purge Gmail Inbox
Log in and in the search are type something like this :
Then "Select all conversations that match this search"
Purge Verizon Inbox
Log in and go to settings >> posts per page >> no limit.
Go back to Inbox and select all messages and delete!
Purge Yahoo Inbox
This is like GMail, you must search the mail for the date range, then select the tick box to select all then hit the trash can to delete.
Note: The Dates must be in quotes, unlike GMail, example below, then hit CNTRL + A plus click the tick box to select All Messages.
Purge AOL Inbox
AOL you just select ALL with the tick box and scroll bar to the bottom. (They don't actually load all the e-mails so you can scroll down quickly)
Purge Comcast/XFinity Inbox
Comcast isn't too bad, just shift+click in the "select all" box then delete.
Purge Hotmail/Microsoft/Live Inbox
The easiest supprisingly! Just click the select all box, then click the words "Select everything" in your inbox. Then Delete!
Go to Manage Folders, then you can delete entire folders.