Instruct: Classify the given review as either positive or negative.
Query: Works very well

I use these all the time for pesky fruit fly problems. It does take about a week to really see a difference, and yes, I agree, you do have to swirl them or the packet of powder settles so really, the worst part is remembering where you place them. After a while, the problem is gone. We seem to have recurring issues in the summer so I keep the lures on hand and the traps are reusable so I recommend them to anyone.