Green’s Dictionary of Slang

beeswax! excl.

[euph. bullshit! excl.]

(N.Z./US) a dismissive excl.; rubbish!

[US]F. Hutchison Philosophy of Johnny the Gent 20: I’ve got about as much idea whether I’m gettin’ the goods or the brace when one o’ them Shakspere guys [...] says ‘Oh, Beeswax!’ .
[NZ] McGill Reed Dict. of N.Z. Sl.