def clean_params
      clean_unserializable_data_from(:parameters)
      filter(parameters)
      if cgi_data
        clean_unserializable_data_from(:cgi_data)
        filter(cgi_data)
      end
      if session_data
        clean_unserializable_data_from(:session_data)
        filter(session_data)
      end
    end
def clean_params
      clean_unserializable_data_from(:parameters)
      filter(parameters)
      if cgi_data
        clean_unserializable_data_from(:cgi_data)
        filter(cgi_data)
      end
      if session_data
        clean_unserializable_data_from(:session_data)
        filter(session_data)
      end
    end
Replaces the contents of params that match params_filters.
 TODO: extract this to a different class