Recovery items in users mailboxes can substantially increase the overall size of your store. If you would like to clear these out of all users mailboxes create the following two script files to use
Flush_recovery_items.cmd
C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe -command “. ‘c:\Program Files\Microsoft\Exchange Server\V14\bin\RemoteExchange.ps1’; Connect-ExchangeServer -auto; cd c:\scripts\ ; .\Flush_recovery_items.ps1”
Flush_recovery_items.ps1
Get-User -RecipientType UserMailBox | Search-Mailbox -SearchDumpsterOnly -DeleteContent -confirm:$false
You will be prompted to continue and can select Y to go mailbox by mailbox, or press A to continue deleting from All mailboxes