My grandmother had, among her myriad knickknacks, an old postage scale. I decided to clean it up.
As you can see it was quite dirty and rusty. Unfortunately it was also mis-calibrated due to an accident in transportation. There was nothing to do but take it apart.
I carefully unscrewed every screw and nut holding it together. I was a little surprised to see that the face of the scale was separate from the rest of the scale, but this makes sense since it would mean one scale could be made to weigh different things. I also imagine that the post-office could send out updated face-plates, but I'm not sure if this happened with this particular model.
The mechanism of the scale is remarkably simple. It is basically a spring-loaded platform that has a toothed-edge which turns a gear. The gear turns the needle. This arrangement is rather tedious to tune, however, and I was not able to get the scale working 100% once re-assembled. If you shake the scale it wiggles loose and is no longer zeroed.
I was, however, able to clean the scale up considerably. The only aspect of this that bothered me is that the paint came off in a couple places on the front of the scale. However it is still a marked improvement. I don't think the postal rates on the face-plate are accurate anymore, but maybe I can get a new faceplate somewhere. Now if only I had a parcel to mail....