Entry revised for OED Online

mucky, a.

DRAFT REVISION Apr. 2007

6. mucky pup colloq., a (habitually) messy or dirty child or (humorously) adult.

H. HEMSLEY Dirty Little Tinker (sheet music), Dirty little muck-pot! Dirty little tyke! That's what Daddy calls me... Dirty little *Mucky Pup, But he loves me just the same.
in R. Miller MS School Exercise Bk. (O.E.D. Archive), [Teacher's comment] Mucky pup! Material..very carelessly expressed. 
'Puncture'  Mucky Pup (song), I pick my nose,..I'm a mucky pup.

1988 M. GEE Grace v. 77 She said I was the muckiest pup in the place, and I end up working as a hotel cleaner. 1998 Evening Chron. (Newcastle) (Nexis) 20 Feb. 8 Its foamy formula stripped chocolate, ink, oil. grease and ingrained grime from the back seat

I didn't realise I was such a mucky pup.