A straight screwdriver
an exacto knife or razor
some 4 x 12 register vent filters (12 of them at home depot for $4)
and of course an aerovac style roomba
The Freakduino-chibi is of course optional.
Step 1: Removing the old filter material
Removing the old filter material isn't difficult, but you have to be careful that you don't break the plastic. Using a razor, first cut the tops and bottoms of each exposed filter element. Next cut the bottom of the edge filter elements on either side.