Some usefull Exchange 2010 powershell scripts for space management

Force remove disconnected database after a move or delete
Remove-StoreMailbox -Database "" -Identity "" -MailboxState SoftDelete

Exchange 2010 Find Database White Space
Get-MailboxDatabase -Status | Select-Object Server,Name,AvailableNewMailboxSpace

Retrieve List of Disconnected Mailboxes
Get-MailboxDatabase | Get-MailboxStatistics | where {$_.DisconnectReason -eq “SoftDeleted”} | Select DisplayName,ServerName,Database,ItemCount

Permanently Delete all Disconnected Mailboxes across all Database
$var1 = Get-MailboxDatabase | Get-MailboxStatistics | where {$_.DisconnectReason -eq “SoftDeleted”}
$var1 | foreach {Remove-StoreMailbox -Database $_.database -Identity $_.mailboxguid -MailboxState SoftDeleted}