#region Remove XML comments
System.Xml.XPath.XPathNavigator path = xmlDoc.SelectSingleNode("w:document",xmlNSMgr).CreateNavigator();
System.Xml.XPath.XPathNodeIterator commentsIterator = path.SelectDescendants(System.Xml.XPath.XPathNodeType.Comment,false);
if (commentsIterator.Count > 0)
{
while (commentsIterator.MoveNext())
{commentsIterator.Current.DeleteSelf();}}
#endregion

For the following XML:-(We needed to remove "<!–  Generated by Aspose.Words for .NET 4.4.1.0   –> ")

  <?xml version="1.0" encoding="utf-8" standalone="yes" ?>
– <w:document xmlns:ve="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships" xmlns:m="http://schemas.openxmlformats.org/officeDocument/2006/math" xmlns:v="urn:schemas-microsoft-com:vml" xmlns:wp="http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawing" xmlns:w10="urn:schemas-microsoft-com:office:word" xmlns:w="http://schemas.openxmlformats.org/wordprocessingml/2006/main" xmlns:wne="http://schemas.microsoft.com/office/word/2006/wordml">
– <!–  Generated by Aspose.Words for .NET 4.4.1.0
  –>
– <w:body>
– <w:p>
– <w:r>
– <w:rPr>
  <w:b />
  <w:color w:val="FF0000" />
  <w:sz w:val="24" />
  </w:rPr>
  <w:t>Evaluation Only. Created with Aspose.Words. Copyright 2003-2007 Aspose Pty Ltd.</w:t>
  </w:r>
  </w:p>
  </w:body>
  </w:document>