So far it is as Jeeves said. They are attracted to hair and cloth, perhaps we can make something from such materials that they will find appealing and use that as bait for trapping them.

[She wasn't about to question his sense of smell since she had heightened eyesight and hearing in comparison to most humans. It certainly sounded useful.]

If you can tell the difference between what is and is not a prop, then that will make capturing them all the easier.