Remove All Exchange 2010 Disconnected Mailboxes

$mailboxes = Get-ExchangeServer | Where-Object {$_.IsMailboxServer –eq $true} | ForEach-Object { Get-MailboxStatistics –Server $_.Name | Where-Object {$_.DisconnectDate –notlike ‘’}} | select displayname, mailboxguid, database
$mailboxes | ForEach { Remove-Mailbox -Database $_.Database -StoreMailboxIdentity $_.MailboxGuid -confirm:$false }
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Set Send on Behalf of Distribution List

Set-DistributionGroup -Identity GroupName -GrantSendOnBehalfTo User1,User2
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Manually Update global address book
Get-GlobalAddressList | Update-GlobalAddressList
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Remove a distribution group
Remove-DistributionGroup -Identity "GROUP ALIAS"