Don't filter out all CSS styling.
Sorry, it’s not possible.
You have wrote nothing about the reasoning behind your request, so we have provided no details with our response either. But we can explain.
Making this a site-wide change would be bad, because most people prefer to read clean content without any additional markup. Making this a per-user change would:
1. drastically increase the amount of disk space we would need to have, since we will need to store unstripped content;
2. increase the CPU time spent in giving out feed content to users who prefer clear text, since we would need to strip unnecessary tags in real time.
We believe that such esoteric feature does not validate that extra amount of site-wide resources we would need to support it. Google, being a multi-billion-dollar corporation running millions of servers could probably afford doing it, but as we can see things did not work that well for their Reader.
However, as you seem to be a business-savvy person, we understand your desire to pay for what you want. If you wish we can prepare a business proposal for you to cover the development effort and increase in our operation cost that this feature will imply. We will be able to start developing it as soon as you clear the invoice.
Please let us know what you think.
Douglas Thrift commented
Wow! Really? Google Reader didn't filter out all CSS, so I'm pretty sure it can be done. I was actually considering paying for this service, but, considering how quickly you dismiss user ideas, I think I will take my business elsewhere.