I can't really think of any way of removing them without making a mess. Try just trapping them or sweeping them out, they'll likely shit themselves in fear. Squishing or spraying is obviously messy. Perhaps you could trick them out on to newspaper or some kind of disposable sticky trap.
Considering that they're house yu, the areas they occupy will need cleaning anyway. The easiest way to minimize paste splatter is to use candy as bait; this will attract all but the unborn and smallest kos. The smallest can just be sucked into a hand-vac.
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