It just looks dirty to me... As long as it runs well, it is worth fixing. The corrosion on the inside of the emptor can be shifted with a small wire brush on something like a dremel tool. I had the same trouble with my 517, only it was deeper corrosion than yours appears to be, it cleaned off but there is still craters in the aluminum where (?) had eaten away at it. The tarnish on the motor housing and rug nozzle can be cleaned with Mothers aluminum polish, and while it isn't overly hard work, it does take time. If you have a buffer that would help a lot (I used a cotton wheel on a dremel tool, but that took a good couple hours as well) With some time and effort that can be restored to almost new, cosmetically and mechanically. Good Luck!