A thought

Perhaps oil will be too much, the quantity for their original plan, given the size of the sewers, would probably not work. But perhaps that, combined with some alcohol (a word derived from Arabic) would be sufficient.
"What if we closed in the main nest, saturated that with oil by using some sort of pumping device, and then used the Osris (Molotov) drink bombs to ignite an explosion around the main nest? It would be easier than saturating the entire sewer, but it would destroy much of the main next."
His mind flashed, remember lessons regarding the Glorious Navy of Torm and its defeat over the infidel using flying flames.

"Could we use a ships pump to launch oil and ignite it midstream? I remember hearing about something like that." He was unsure, as the history classes in the citadel were many years ago, but it sounded like it had possibilities.