PS C:\Windows\system32> Get-ChildItem -Path WSMan:\localhost\ClientCertificate


   WSManConfig: Microsoft.WSMan.Management\WSMan::localhost\ClientCertificate

Type            Keys                                Name
----            ----                                ----
Container       {URI=*, Issuer=C9FEFC763D9548B48... ClientCertificate_144623306

Get-ChildItem -Path WSMan:\localhost\ClientCertificate

Remove-Item -Recurse -Path WSMan:\localhost\ClientCertificate\*