Deep copy of Hashtable

In order to solve my problem of returning a hashtable by reference (see previous post), I first tried to use Hashtable.Clone() to give me a copy of the hashtable. However since Clone() only does a shallow copy of the hashtable, this did not work since the hashtable contained Objects and changing them in the calling code caused side-effects in the originating class. So what was needed was a deep copy of the hashtable and this proved to be really simple:

       private Hashtable mMeasurements = new Hashtable();
       ...
       MemoryStream ms = new MemoryStream();
       BinaryFormatter bf = new BinaryFormatter();
       bf.Serialize(ms,mMeasurements);

       ms.Seek(0,SeekOrigin.Begin);
       clonedMeasurements = (Hashtable)bf.Deserialize(ms);

Are there any concerns regarding this code?