There’s a lot of articles or forums regarding this issue of removing namespaces in xml. Here are a list of solutions compiled from other resources that I found useful. Pick and use based on your preferable solution.

Using a simple xml below as an example;

1. Using LINQ to XML
   1. static XElement stripNS(XElement root) {
   2.  return new XElement( root.Name.LocalName, root.HasElements ? root.Elements().Select(el => stripNS(el)) : (object)root.Value );
   3. }
   4.  
   5. static void Main() {
   6.  var xml = XElement.Parse(@"<Root xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
   7.  <Item>
   8.    <Code xmlns="http://schema.peters.com/doc_353/1/Types">0174587</Code>
   9.    <AltCode xmlns="http://schema.peters.com/doc_353/1/Types">014717</AltCode>
   10.    <supplier xmlns="http://schema.peters.com/doc_353/1/Types">019172</supplier>
   11.    <ID xmlns="http://schema.peters.com/doc_353/1/Types" />
   12.    <type3 xmlns="http://schema.peters.com/doc_353/1/Types">
   13.      <AltCode />
   14.      <main>false</main>
   15.    </type3>
   16.    <status xmlns="http://schema.peters.com/doc_353/1/Types">Some state</status>
   17.  </Item>
   18. </Root>");
   19.  Console.WriteLine(stripNS(xml));
   20. }
   1.   static XElement stripNS(XElement root)
   2.     {
   3.         XElement res = new XElement(
   4.             root.Name.LocalName,
   5.             root.HasElements ?
   6.                 root.Elements().Select(el => stripNS(el)) :
   7.                 (object)root.Value
   8.         );
   9.  
   10.         res.ReplaceAttributes(
   11.             root.Attributes().Where(attr => (!attr.IsNamespaceDeclaration)));
   12.  
   13.         return res;
   14.     }
   1. Public Function RemoveAllNamespaces(ByVal element As XElement) As XElement
   2.         If element.HasElements Then
   3.             Dim cleanElement = RemoveAllNamespaces(New XElement(element.Name.LocalName, element.Attributes))
   4.             cleanElement.Add(element.Elements.Select(Function(el) RemoveAllNamespaces(el)))
   5.             Return cleanElement
   6.         Else
   7.             Dim allAttributesExceptNamespaces = element.Attributes.Where(Function(attr) Not attr.IsNamespaceDeclaration)
   8.             element.ReplaceAttributes(allAttributesExceptNamespaces)
   9.             Return element
   10.         End If
   11.  
   12.     End Function
2. Using XLT
   1. <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">  
   2.  <xsl:output method="xml" indent="no" encoding="UTF-8"/>  
   3.  <xsl:template match="/|comment()|processing-instruction()">    
   4.   <xsl:copy>      
   5.    <xsl:apply-templates/>    
   6.   </xsl:copy>  
   7.  </xsl:template>  
   8.  <xsl:template match="*">    
   9.   <xsl:element name="{local-name()}">      
   10.    <xsl:apply-templates select="@*|node()"/>    
   11.   </xsl:element>  
   12.  </xsl:template>  
   13.  <xsl:template match="@*">    
   14.   <xsl:attribute name="{local-name()}">      
   15.    <xsl:value-of select="."/>    
   16.   </xsl:attribute>  
   17.  </xsl:template>
   18. </xsl:stylesheet>
3. Using Regular expression
   1. string XMLPattern = "xmlns=\\\".+\\\"";
   2. Regex regXML = new Regex(pattern);
   3. string XMLInput = FancyMethodThatPutsXMLIntoString();
   4. string Results = regXML.Replace(XMLInput, "");
   Note: The triple slashes serve to escape the escaping of the quotes for your regex formula. Technically the formula is xmlns=\”.+\”

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