Removing items from the Office 365 Search Index - Cloud hybrid Search

Reference Link:Removing items from the Office 365 Search Index

Script:
<#

.SYNOPSIS
    Issue a call to SPO to delete all external content indexed through Cloud hybrid search. This operation is asynchronous.
.PARAMETER PortalUrl
    SharePoint Online portal URL, for example 'https://contoso.sharepoint.com'.
.PARAMETER Credential
    Logon credential for tenant admin. Will prompt for credential if not specified.
#>
param(
    [Parameter(Mandatory=$true, HelpMessage="SharePoint Online portal URL (PPE), for example https://contoso.spoppe.com.")]
    [ValidateNotNullOrEmpty()]
    [String] $PortalUrl,
    [Parameter(Mandatory=$false, HelpMessage="Logon credential for tenant admin. Will be prompted if not specified.")]
    [PSCredential] $Credential
)

$SP_VERSION = "15"
$regKey = Get-ItemProperty -Path "HKLM:\SOFTWARE\Microsoft\Office Server\15.0\Search" -ErrorAction SilentlyContinue
if ($regKey -eq $null) {
    $regKey = Get-ItemProperty -Path "HKLM:\SOFTWARE\Microsoft\Office Server\16.0\Search" -ErrorAction SilentlyContinue
    if ($regKey -eq $null) {
        throw "Unable to detect SharePoint installation."
    }
    $SP_VERSION = "16"
}

Add-Type -AssemblyName ("Microsoft.SharePoint.Client, Version=$SP_VERSION.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c")
Add-Type -AssemblyName ("Microsoft.SharePoint.Client.Search, Version=$SP_VERSION.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c")
Add-Type -AssemblyName ("Microsoft.SharePoint.Client.Runtime, Version=$SP_VERSION.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c")

if ($Credential -eq $null)
{
    $Credential = Get-Credential -Message "SPO tenant admin credential"
}

$context = New-Object Microsoft.SharePoint.Client.ClientContext($PortalUrl)
$spocred = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($Credential.UserName, $Credential.Password)
$context.Credentials = $spocred

$manager = New-Object Microsoft.SharePoint.Client.Search.ContentPush.PushTenantManager $context
$task = $manager.DeleteAllCloudHybridSearchContent()
$context.ExecuteQuery()

Write-Host "Started delete task (id=$($task.Value))"

Record this task ID as you may need it if calling Microsoft Support should the process for any reason fail. The task is asynchronous, that is, you can leave it to continue on running in the Office 365 Search Farm and it will eventually complete.

After this final step you will get no more feedback but you can track the effect of the task by running a search query for the managed property IsExternalContent=1 . The screen shots below were taken just before the purge, then a short time later and you can see the reduction in the estimated item count for the same query.