I noticed some tiny brown flecks on my girls' hair a few weeks ago, much like finely ground coffee, and looked into this. They've been scratching like crazy so I did a deep clean of the cage, binned or washed old toys etc, bathed, cut hair and put spot on on both piggies. To no avail it seems, as both are still scratching away. Anyone have any idea a) what it is exactly and b) how to get rid for good? (Ps anything likely to linger on humans or human clothes?)