$strservers = 'C:\servers.txt'
$Servers = Get-Content $strservers

foreach ($Server in $Servers){
    $computer = [ADSI]("WinNT://" + $Server + ",computer")
    $group = $computer.psbase.children.find("Administrators")
    $userToRemove = "DOMAIN/User"
    $group.Remove("WinNT://$userToRemove")
}

Add a code snippet to your website: www.paste.org