title: Removing attributes of columns in data.frames on multilevel lists in R
body: <p>How do I remove the attributes of the following columns of data.frames on a nested list in R on the fly?   </p>
  
  <pre><code>List of 1
   $ 0021400001:List of 19
     $ GameSummary      :'data.frame':    1 obs. of  13 variables:
      $ GAME_DATE_EST                   : Factor w/ 1 level "2014-11-09T00:00:00": 1
        - attr(*, "names")= chr "1"
      $ GAME_SEQUENCE                   : Factor w/ 1 level "2": 1
        - attr(*, "names")= chr "2"
      $ GAME_ID                         : Factor w/ 1 level "0021400091": 1
        - attr(*, "names")= chr "3"
      $ GAME_STATUS_ID                  : Factor w/ 1 level "3": 1
        - attr(*, "names")= chr "4" 
     $ SeasonSeries     :'data.frame':    1 obs. of  7 variables:
       $ GAME_ID         : Factor w/ 1 level "0021400001": 1
        - attr(*, "names")= chr "1"
       $ HOME_TEAM_ID    : Factor w/ 1 level "1610612740": 1
        - attr(*, "names")= chr "2"
       $ VISITOR_TEAM_ID : Factor w/ 1 level "1610612753": 1
        - attr(*, "names")= chr "3"
  </code></pre>