Ectoplalm
This stuff replaces regular napalm for the flamethrower (use the stats for the weapon found on page 37 of The Day After Ragnarok). It does considerably less damage (2d6) to normal targets, but it is pure death on Serpent-Tainted objects and monsters (3d10). Bizarrely, Ectoplalm acts as an extinguishing agent on ophiline (refined Serpent oil). If used on the countryside, a full tank of Ectoplalm can reduce the Serpent Taint of a quarter acre of land by 1. This is of course done by burning everything down to the grassroots, but it works.
What’s the giggest problem with Ectoplalm? Well, to make Ectoplalm you need to refine either herpetol (ophiline – enhanced gasoline) or ophethanol (ophiline – enhanced ethanol) in an area that was the site of a mass murder. This is known; what the refiners keep secret is that, if one murder site is used too often, the amount of Ectoplalm that can be harvested gets smaller and smaller. But another death on the site brings production right back up! Which has led some of the more desperate would-be ophethanol manufacturers in Kentucky to start thinking about making equally desperate decisions.