CORrection FLUid, a substance in much demand during the low-tech, pre-computer days of fanzines.
Fandom Is A Way of Life.
Letter of Comment, a response to the material in a zine, meant to give the authors and editor feedback.
See fanzine. An amateur SF publication (often shortened to zine) sometimes including stories, con reports, book reviews, articles of fannish interest, and almost always LoCs.