Here's a throwaway Python script to clean up HTML produced by Microsoft Excel 2010. I leave it here just so that I can find it later, or if anybody else has the same problem -- for some reason, I couldn't google an easy solution anywhere. I'm sure this doesn't cover all the corner cases and complex layouts, but it's a starting point showing most of the techniques you'll ever need: tag stripping, attribute stripping (either en-masse or selective), and handling crappy declarations ("<!if" tags).
It's for Python 3 (although I think it'll work almost unmodified in 2.7, you'll just have to change open() calls with codecs.open()) and requires BeautifulSoup 4+, which really does all the magic. I don't know if it's the power of Py3k or BS getting better and better, but it's gone through a dozen files in a blink.
