I love the old machines. Don't use them for parts. They are beautiful. And a great reminder of how technology used to be. Just think, what you are using right now will be considered junk in 10 years... The real old ones like the Powerbook 100, should be kept; eventually people will throw these old computers away and then there won't be that many left. Even though they aren't that useful, it's fun to fire them up and remember how it was. Or for some people who never used these "state of the art" machines back in the '90's... it's a reminder of how far we have come. They still work (maybe after you change the capacitors)... and do whatever we did on them years ago.
My clicker stopped working right out of the blue. And so I read stuff here and on the Apple site. Decided to remove the back of the macbook air case... and sure enough, half the battery is slightly puffy. I unscrewed all the screws on the battery, lifted it out (but did not detach it). Checked to see if the clicker worked. Sure enough it worked fine. Put everything back the way I took it out; and now it works fine. The batteries can swell when it gets hot. Evenutally this will probably do this again, so in the meantime I'll look for a new battery. So don't buy that trackpad until you try this.