Easy way to delete all the emails from a users mail box - outlook 2010

The mail box user name is JPH
Please post me the right Cmdlet  to delete mails from : Inbox, sent items , and Deleted items

Thanks

I trield this command from the exchange management shell and I get this error, not sure if I am making a mistake.

[PS] C:\Windows\system32>Get-Mailbox -identity jph | Export-Mailbox -TargetMailb
ox "exportmailbox" -TargetFolder "jph" -deletecontent
The specified user "exportmailbox" could not be found.
At line:1 char:1
+ Get-Mailbox -identity jph | Export-Mailbox -TargetMailbox "exportmailbox"
-Targe ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~~
    + CategoryInfo          : NotSpecified: (:) [], ManagementObjectNotFoundEx
   ception
    + FullyQualifiedErrorId : 98333571

[PS] C:\Windows\system32>Get-Mailbox -identity jph | Export-Mailbox -TargetMailb
ox "exportmailbox" -TargetFolder "jph" -deletecontent

Hi Guys

I followed this link

https://www.experts-exchange.com/questions/28311617/Delete-Users-Exchange-2010-Mailbox-and-recreate-new.html

Please help me if I have made any mistake I went to the  Exchange 2007 Management Console, Right-click the mailbox user and select "Disable" . I went into the disconnected mailbox folder and cant see the disconnected user now.
But still I created a new mail box for this user and since after creating this mail box I can see some mails have come to this mail box. but emails sent by some staff are not getting through and it comes with the following message

Delivery has failed to these recipients or distribution lists:

JPH
The recipient's e-mail address was not found in the recipient's e-mail system. Microsoft Exchange will not try to redeliver this message for you. Please check the e-mail address and try resending this message, or provide the following diagnostic text to your system administrator.

So not sure what is happening , please suggest me how to resolve this. Also I sent an email to this user and it is 30 minutes ago and the mail had not popped on the users inbox.

Thanks

The database name is "Staff" Is the below syntax correct

clean-mailboxdatabase -database <Staff>

Also when I send email to JPH from my OWA the mail is received on the JPH mail box.
But if I send it from outlook client the mail doesn't appear on JPH inbox. I cleared auto complete  and no cashing at the moment.
I don't get any NDR report, not sure where the mail goes.

thanks

Thanks Will

Hi Will

When I give the clean database command , how long will it take to clean.
During this process will the exchange be down.

Thanks