title: Mongo convert all numeric fields that are stored as string
body: <p>It looks like for a while now I've been storing my decimals as strings. This is now a problem because I need to start using the aggregation framework to perform some calculations.</p>
  
  <p>Is there any way to walk each document in my collection and check each value for <code>isNaN</code>, and if false, store it with <code>parseFloat</code></p>