I also discovered that a shopvac does wonderful things for loose styrofoam peanuts, but that it was necessary to clean your air filter once in a while. Mine was plugged pretty effectively with rabbit fur from the time before the last time Texie moved her buns into my place. Given that my filter is a pretty basic design, it's certainly possible to clean it. I started off picking fur off of it (which I started indoors... that turned out great) and moved upwards to whacking it against things to remove sawdust, but the coughing which ensued educated me that it probably wasn't the right way to go about it. I resolved to use the shopvac in blower mode, to blast the sawdust and rabbit fur off of it from the inside. However, I also resolved not to do it tonight because it wouldn't be appreciated at 1am or so.
So, to see how THAT turned out, check out the next day's entry.