Probably the easiest method is to do an H&E with prolonged washing after the eosin staining (1). Sirius Red will also stain eosinophils (apart from amyloid) (2).
Mike Rentsch (3) suggests that any of the Romanowsky stains will work well on sections ie. Giemsa, Leishman, or Wrights but you will need a pH of 6.4 or even 6.0 rather than the 6.8 Haematology use. Your routine H&E will also do extremely well if you use a buffered eosin pH5.2-5.4 as will also EA50 from Cytology which has the same pH.
One method that some have used is Duffy, J. P.; Smith, P. J.; Crocker J. and Matthews H. R. "Combined Staining Method for the Demonstration of Tissue Eosinophils and Mast Cells" J. Histotechnology, June 1993, pp 143-144.
Ian Montgomery (4) suggests the following method:
Lendrum. 1944. J.Path.Bact. 56. 441.
Simple and selective technique for eosinophils. The presence of phenol lowers the pH of the stain increasing the selectivity for the eosinophilic granules.
The stain keeps for up to 3 months.