Two more mailboxes were blown up by homemade bombs in West Des Moines. So how are they doing it? They are using household chemicals inside of a plastic bottle. The recipe is on YouTube. I've posted about it before. More likely than not, they are using Drano and aluminum foil.
3600 Block of Western Hills
2500 Block of Maple Street
Is there a pattern to the location
Here is a little different method using a water bottle, saran wrap, vinegar and some baking soda.