Insert a Pandas Dataframe into mongodb using PyMongo

What is the quickest way to insert a pandas DataFrame into mongodb using PyMongo?

Attempts

db.myCollection.insert(df.to_dict())

gave an error InvalidDocument: documents must have only string keys, key was Timestamp('2013-11-23 13:31:00', tz=None)

db.myCollection.insert(df.to_json())

gave an error TypeError: 'str' object does not support item assignment

db.myCollection.insert({id: df.to_json()})

gave an error InvalidDocument: documents must have only string keys, key was <built-in function id>

df

<class 'pandas.core.frame.DataFrame'>
DatetimeIndex: 150 entries, 2013-11-23 13:31:26 to 2013-11-23 13:24:07
Data columns (total 3 columns):
amount    150  non-null values
price     150  non-null values
tid       150  non-null values
dtypes: float64(2), int64(1)