RE: "these words are not real English and he has made them up."

well, as we've seen, this was an ill-considered opinion with regard to these words; in fact, manky is already in the OED and has only been coarsened in slang -- perhaps skanky in the nasty sense comes from rhyming slang.

manky - Bad, inferior, defective; dirty.
Possibly influenced by Fr. manqué.

-joe (don't say hanky-panky to an OP) friday