John S. Farmer, Slang and its analogues past and present…
“ Up the flue (or spout) , adj. phr. (colloquial) .—Dead; collapsed, mentally or physically. To be up one’s flue, verb. phr. (colloquial) .—To be awkward for one. That’s up your flue = That’s a ‘facer,’ or that’s up against you. Flue-Faker (or Scraper) , subs. (common) .—A chimney-sweep. [From Flue + Faker (q.v.) .] Minor clergy = young chimney sweeps. For synonyms, see Clergyman. 1821. Egan, Tom and Jerry, p. 60. The ‘office’ has been given to ‘shove’ the poor flue-faker against Tom’s light drab coat. 1859. Matsell, Vocabulum, or Rogue’s Lexicon, s.v. ”
