Have you done alternative stains on this material? Giemsa, PAS ? it would be interesting if this is a proper colour of the macrophages or just a matter of binding Orange G (out of the PAP-stain).

If it is bilirubin, there is a stain called "Hall" or "Fouchet"  to show liver-pigments.

The macrophages maycontain metabolic remnants of phagocytized red blood cells. Have look on the following report: Recenti Prog Med. 1992 May;83(5):295-7.

False positivity of tumor markers in pleural fluid of traumatic hemothorax.

Foresti V1, Parisio E, De Filippi G

I agree with Gudrun Lang. To see if is hemosiderin laden make Prussian blue 

Another option is just to look a ta native smear w/o staining and see the natural colour of the pigment. At least it can give a clue for the origin.

Prussian blue and bile pigment stains are a must in that case.

This is not surprising as a classic Pap stain carries  five dyes in three solutions-

1. A nuclear stain (hematoxylin)

2. First OG-6 counter stain (Orange G)

3. Second EA (Eosin Azure) counter stain having three dyes, viz., Eosin Y,  Light Green SF or Fast Green FCF and  Bismarck brown Y (not used anymore).

The yellowish green color of macrophage cytoplasm seems to be due to one of the dyes in your counter stain.