:: This script searches the TEST folder and subfolders, \
:: then deletes files older than 21 days.
::

 
:: If you want to make it more robust, you can add a timestamp to the file, 
:: so that you know when it was deleted
:: $myDate = get-date -format -g
:: $content = $myDate  + "   " + $File.FullName
:: Add-Content $LogFile $content

cls
$Now = Get-Date 
$Days = "21" 
$Targetfolder = "c:\TEST" 
$LogFile = "C:\DeletedFiles.txt"
#----- define LastWriteTime parameter based on $Days ---# 
$LastWrite = $Now.AddDays(-$Days) 
#----- get files based on lastwrite filter and specified folder ---# 
$Files = Get-Childitem $TargetFolder -Include $Extension -Exclude *.xml -Recurse | 
        where {$_.LastWriteTime -le "$LastWrite"} 
        foreach ($File in $Files) { 
            if ($File -ne $Null) { 
                Add-Content $LogFile $File.FullName
                write-host "Deleting File --> $File" -ForegroundColor "Green" Remove-Item $File.FullName | out-null 
            } 
        }