I'm reviving my long sleeping Sport 22, which has been stored on jacks for almost four years. After reading this forum, and watching related You Tube instructional videos, I'm doing my own hub service for the first time. Removing, cleaning, inspecting, and re-greasing the bearings is not as tough as I expected, and the brakes look good. Thanks again to all in this forum for great advice, and encouraging folks to take an active role in learning Airstream sub-systems!
I've used a product called Brakleen, which works great on all the metal and brake surfaces. The strange white spot is a clean shop towel, keeping dirt out of the bearing traces while I clean the bearings.