Decomission an SDL Tridion 2013 SP1 Publishing Target with PowerShell and Core Service. See http://tridion.stackexchange.com/questions/12701/how-to-decomission-a-publishing-target-with-powershell
# Make sure Tridion-PowerShell-Modules is installed fist https://github.com/pkjaer/tridion-powershell-modules
Import-Module Tridion-CoreService
Set-TridionCoreServiceSettings -Version 2013-SP1
$client = Get-TridionCoreServiceClient
# Listing the publication targets does not work for Sites 9 and up
#$filter = New-Object Tridion.ContentManager.CoreService.Client.PublicationTargetsFilterData;
#$client.GetSystemWideList($filter)
# brute-force discover publicaton targets
Get-TridionItem tcm:0-1-65537 | Select-Object Id, Title
Get-TridionItem tcm:0-2-65537 | Select-Object Id, Title
Get-TridionItem tcm:0-3-65537 | Select-Object Id, Title
Get-TridionItem tcm:0-4-65537 | Select-Object Id, Title
Get-TridionItem tcm:0-5-65537 | Select-Object Id, Title
Get-TridionItem tcm:0-6-65537 | Select-Object Id, Title
Get-TridionItem tcm:0-7-65537 | Select-Object Id, Title
Get-TridionItem tcm:0-8-65537 | Select-Object Id, Title
Get-TridionItem tcm:0-9-65537 | Select-Object Id, Title
Get-TridionItem tcm:0-10-65537 | Select-Object Id, Title
$client.DecommissionPublicationTarget("remove-me-tcm:0-1-65537")