Static Electricity problem

Hi, I've been asked to make a Christmas display, that has a glass bowl mounted on top of a fan with polystyrene balls, 6mm dia, that blow trough a hole above the fan, there is fly wire above the fan. My problem is, that static electricity make all the balls bunch up on top preventing them coming into the airflow and stopping excess air escaping. Does anyone have any ideas on preventing this from occurring.

Thanks in advance,
Kryn