How to strip non-alphanumeric chars from a string

The example below also leaves the space character and commas intact.

      private string StripSpecialChars(string inputString)
      {
         return (Regex.Replace(StripHTML(inputString), "[^A-Za-z0-9 ,]", ""));
      }

How to strip HTML tags out of a string

      static string StripHTML(string inputString)
      {
         return Regex.Replace
           (inputString, "<.*?>", string.Empty);
      }