PowerShell to delete unused Crawl Properties

PowerShell to delete unused Crawl Properties:

Add-PSSnapin "Microsoft.SharePoint.PowerShell"

$searchApp = Get-SPEnterpriseSearchServiceApplication "Search Service Application"

$schema = New-Object Microsoft.Office.Server.Search.Administration.Schema –ArgumentList $searchApp

$category = $schema.AllCategories["SharePoint"];

$category.DeleteUnmappedProperties();  

$category.Update();