how to make letter bombs?

You will first have to make a mild version of thermite. Use my recipe, but substitute iron fillings for rust.

Mix the iron with aluminum fillings in a ratio of 75% aluminum to 25% iron. This mixture will burn violently in a closed space (such as an envelope). This bring us to our next ingredient...

Go to the post office and buy an insulated (padded) envelope. You know, the type that is double layered. Separate the layers and place the mild thermite in the main section, where the letter would go. Then place magnesium powder in the outer layer. There is your bomb!!

Now to light it... this is the tricky part and hard to explain. Just keep experimenting until you get something that works. The fuse is just that touch explosive I have told you about in another one of my anarchy files. You might want to wrap it like a long cigarette and then place it at the top of the envelope in the outer layer (on top of the powdered magnesium). When the touch explosive is torn or even squeezed hard it will ignite the powdered magnesium (sort of a flash light) and then it will burn the mild thermite. If the thermite didn't blow up, it would at least burn the fuck out of your enemy (it does wonders on human flesh!).