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private string RemoveNonAlphaChars(string txt)
{
string returnText = txt;

returnText = returnText.Replace("~", "");
returnText = returnText.Replace("`", "");
returnText = returnText.Replace("!", "");
returnText = returnText.Replace("@", "");
returnText = returnText.Replace("#", "");
returnText = returnText.Replace("$", "");
returnText = returnText.Replace("%", "");
returnText = returnText.Replace("^", "");
returnText = returnText.Replace("&", "");
returnText = returnText.Replace("*", "");
returnText = returnText.Replace("(", "");
returnText = returnText.Replace(")", "");
returnText = returnText.Replace("-", "");
returnText = returnText.Replace("_", "");
returnText = returnText.Replace("+", "");
returnText = returnText.Replace("=", "");
returnText = returnText.Replace("{", "");
returnText = returnText.Replace("}", "");
returnText = returnText.Replace("[", "");
returnText = returnText.Replace("]", "");
returnText = returnText.Replace("|", "");
returnText = returnText.Replace("\\", "");
returnText = returnText.Replace("\"", "");
returnText = returnText.Replace("'", "");
returnText = returnText.Replace(";", "");
returnText = returnText.Replace("<", "");
returnText = returnText.Replace(",", "");
returnText = returnText.Replace(">", "");
returnText = returnText.Replace(".", "");
returnText = returnText.Replace("/", "");
returnText = returnText.Replace("?", "");
returnText = returnText.Replace(" ", "");

return returnText.ToUpper();
}