I use a product called " Dust off" Which is compressed air used to clean keyboards I think. Its cheap, found in walmart, and gets the job done fast/ humanely.

I stick them in a container and fill it up, and few seconds later fill it up again to make sure it works. This works from 2-3 weeks+ to adults. I'm a live feeder person but I use it if I have a rat or asf in pain or reached a point where they are not producing.