From Discworld MUD Wiki
There are more than one kind of guano.
Bat guano is a food and a continuous medium.
- Like most foods, it will rot if it has not been dried or cured.
- It can also be rolled into cigarettes using cigarette paper.
- It is produced by giant fruitbats after they have fed.
- It is possible to hasten the guano production by squeezing the bat after feeding.
- Eating bat guano makes someone crave for more, make them do chats and squeeze any fruitbats nearby looking expectantly.
Pigeon guano can be acquired from the top of the AM Post office by scraping it up with an appropriate implement
Guano is used in the nitrolator in the Alchemists' Guild to make nitrate.