Bottle Blower OQ

I need help with plastic bottle blower operational qualification. How can I prove the efficiency of the bottle blower?
I did a little experiment with a litlle plastic particles deliberately filled in the bottles and then weighed once they passed through the bottle blower however I have recieved faulty results (efficiency in removing 50-200%).

The problem is that this test with particulate matters is more less for glass bottles but we use the plastic ones only. How can I prove that they are dust free?

Thank you for your help in advance,