Or ignore them altogether.

Mostly they should have been used to web not working properly. Also it's obvious that they do not care or are unable to install better browser.

What percentage of those 4% who use IE6 actually buy something? Is it worth supporting them? Or you could create an awesome site to sell your stuff more easily.

Yes, I can't even imagine who would normally use it, unless it's some weird static environment with ancient Windows installed which can't be upgraded or something the like. And probably in such case people should have alternative computers for normal browsing.

Well, they also probably know that most sites won't look perfect in their old browser.

Don't bother getting animations to work in IE6, but make sure your site runs okay without them. The latter is doable.

I had to use IE6 for real about a month ago. It wasn't a test. It was the only way I could figure out to get a relative's personal data off an old, damaged PC they hadn't used for years. I managed to get gmail to work in IE6 and email the important files to myself. There was no way I could have updated the browser on that thing; it was a miracle I could even run the browser it already had. Gmail actually made me click a button stating something like "I can not upgrade this browser" before it would let me in, but it worked.

If you have a website that does something useful for its users (and not just making a big, splashy presentation of the wonders of you) I like the idea of having a very stripped down fallback version with nothing but functionality that can be used on browsers with no CSS or Javascript at all. Sometimes even those of us who build websites and spend our days in dev versions of Firefox and Chrome have to use an obsolete browser to get some work done.