[Brett Merkey]

I agree with the comments that Kindle's problem in this regard is partly a too rigid specification of fonts in the style file. There is a Calibre tool that takes care of this, not only wiping out all font-family references but also @font-face declarations and any embedded font files in the book directories:

Edit window > Tools > Manage Fonts

The tool will flexibly allow you to retain certain fonts, or generic sans-serif, etc. while deleting the rest. I use Manage Fonts so often, I keep it on the main edit toolbar.