I keep rediscovering this, so it might be a good idea to write it down: the best and cleanest way to get good-quality EPS files from Excel (Excel 2010, in particular):

  1. Highlight the chart in Excel. Save the file as PDF.
  2. Next, run pdftops to produce a Postscript file. (Do not use the -eps option.)
  3. Next, run ps2epsi to convert the Postscript file to an EPS file with preview (epsi).
  4. Finally, using the vi editor, just remove the preview image from the EPS file "by hand".