I used to dump my tanks out, wash them, dry them, then set back up. It works very well, but was taking way too much time. Now I do it the easy way.....
I use an old license plate to push everybody to one corner of the tank (same corner the babies are in)... turn on the shop vac, and suck up all the old stuff. Then I throw a handful of new pine in and bingo, I am done. I can litterally clean 15 tanks in less then 30 minutes. I might wash the tanks out every once in a while, but it has been 2 months since the last washing, and they still don't need it.
If you want to try this method, make sure the shop vac is OUTSIDE when you use it!!!! otherwise the cloud of funk could kill you!
OP, as you can see by my methods that does not result in any babies deaths, you don't have anything to worry about.