Remove-WebAppHostCruft.ps1

<#
.SYNOPSIS
Removes unused web application settings that have accumulated.

.LINK
Get-Website

.LINK
Get-WebApplication

.LINK
Remove-Xml.ps1

.EXAMPLE
Remove-WebAppHostCruft.ps1 -WhatIf

Shows what settings would be removed.
#>

#Requires -Version 3
#Requires -Module WebAdministration
[CmdletBinding(SupportsShouldProcess=$true,ConfirmImpact='High')][OutputType([void])] Param()
foreach($website in Get-Website)
{
    $name,$path = $website.Name,$website.PhysicalPath
    Select-Xml "/configuration/location[starts-with(@path,'$name/')]" $env:SystemRoot\System32\inetsrv\config\applicationHost.config |
        Where-Object {$app = $_.Node.Attributes['path'].Value -replace "\A$name/",''; !(Test-Path $path\$app -PathType Container) -and !(Get-WebApplication -Site $name $app)} |
        Where-Object {$PSCmdlet.ShouldProcess($_.Node.Attributes['path'].Value,'remove')} |
        Remove-Xml.ps1 -Verbose
}