i take it that the one you dropped was still a little tacky from what it picked up. Last time I did something similar (negs touched the shirt i was wearing, and it picked up a shedload of hairs. I snipped the affected one from the strip, dropped it back into the spiral and gave it a couple of rinses using aired water and a wetting agent (read some ecover washing up liquid) followed by 5 minutes more under a running tap - it pretty much shifted everything!