prophets of gloom are at it again, page-3

Did you know that the bleach that they use to treat the rags on their heads (hence the title RagHead) consists of lysergic acid diethylamide otherwise know to the layman as LSD. The heat generated from their thobbing thoughts makes them sweat and this mixes with the lysergic acid diethylamide in the rags, some of this runs down their face and into the crevases of their mouths.

You can guess the Logic in that.