Cleaning the name dictionaries

string[] filesToClean = new string[]
{
    "names_male.dic",
    "names_female.dic",
    "names_last.dic"
};

foreach (var fileName in filesToClean)
{
    Regex regularExpression = new Regex("[A-Z]{1,16}", RegexOptions.IgnoreCase);

    FileStream fileStream = new FileStream(fileName, FileMode.Open, FileAccess.ReadWrite);
    StreamReader streamReader = new StreamReader(fileStream);

    FileStream tempFileStream = new FileStream(fileName + ".temp", FileMode.CreateNew, FileAccess.ReadWrite);
    StreamWriter streamWriter = new StreamWriter(tempFileStream);

    while (streamReader.Peek() != -1)
    {
        string line = streamReader.ReadLine();
        string cleanLine = regularExpression.Match(line).Value;

        streamWriter.WriteLine(cleanLine);
        streamWriter.Flush();
    }

    streamWriter.Close();
    streamReader.Close();

    File.Delete(fileName);
    File.Move(fileName + ".temp", fileName);
}