Green’s Dictionary of Slang

clog n.

(US black) a gun [? the shape; it too is a squat, heavy ‘lump’].

[US]L. Stavsky et al. A2Z.

In compounds

clog wog (n.)

(Aus.) a person from Holland or Scandinavia [the trad. footwear + wog n.1 ].

[Aus]Betoota-isms 183: Clog Wog [...] 1. A person of Dutch or Scandinavian background.