I went on ebay and bought several roomba 400 series. I picked these for the sole reason that they were about 10$ each (when they were marked as broken). Fully working models were going for 40$. I figured I could buy four broken models for that cost and have enough parts to get at least one working. They finally arrived and the first thing that came to mind was how dirty they were. I guess this is to be expected as they are vacuum cleaners :)
So the first thing I did was strip everything off the models and remove all the brushes and motors associated with its true purpose: vacuuming. I put all the unnecessary pieces to the side. Then I removed all the electronics, sensors, and motors and put them to the side. I then set about washing and scrubbing the dirt off the chassis. Here are some before shots of the robots.
These images do not really convey the level of dirt involved. Next I used some pressurized air to clean dirt off the electronics and wheels. Finally put the wheels and basic electronics back together. I left off most of the sensors for now, figuring I would get the basics to work first. Besides I am mostly interested in just using the wheels for mobility, the battery for power, and the encoders for odometry. I will then mount a camera, the Arduino and some form of processing board (maybe a PC104) on it for image processing. Here is the reassembled shell all nice and clean.