I have a Gene Cafe that I have been using at home for some time. On inital reading of the directions, it recommends washing the roasting chamber:
Oils and residual debris remaining from the roasting process will build up and adversely affect the taste of future batches. Clean the chamber using a dish washing brush, sponge and dish washing liquid. Dry the chamber completely before storing it away.
However, I know that there is a lot of juju surrounding the seasoning of commercial roasters. I've wiped the inside out on a couple of occasions with a cloth when I've accidently over roasted and ended up with a lot of oil in there. If I leave a lot of oil in the chamber, it seems to shorten the end roast times of future batches (they move through the later stages of roasting too quickly to be well controlled).
So basically, to clean, or not to clean?