A brief report on cleaning up a Spong No 1 grinder. A friend asked us to do this after she retrieved it from the garage and found it completely jammed. These are easily disassembled, two screws on the back, easily removed for this one. Below is a picture of what was inside. Lots of black ooze, especially in the base of the burr (next to the body in the pic). 
This looks awful, but in this case removing it only took a few minutes. We then used a steel brush etc to tidy up the rust and it was looking pretty good, as in the second pic. 
This pic shows what they are like inside. The burr is standing up (the handle screws into the end). The burr carrier (the body of the grinder, below the funnel) is just behind the burr. It's a nicely designed burr, in pretty good nick in this example. Below middle is the back of the grinder. This shows the pressure plate (with indent in the middle of it) over which the base of the burr fits. This holds the burr in place to maintain a given grind adjustment. In front of the burr are the two scews that hold the grinder together, and the L-shaped adjustment screw that goes in the back. Note the locking nut on this -- it is neede to hold the grind level in place, and is sometimes missing (take care if buying secondhand!). There are some more pictures here: https://picasaweb.google.com/haazbean/SpongGrinderRenovation
