Gee - just what we needed: a new, scientific way to destroy hobby materials.
The Hancock telescope is the only problem I've ever had with brass, but I've had a couple of interesting experiences with "lead disease."
When I was working at the Mariners' Museum one of my more interesting projects was to conserve (or try to conserve) its collection of WWII U.S. Navy recognition models. (The museum had a fairly complete set - both the 1/500 "teacher models" and the 1/1200 "student models.") As I imagine most readers of the Forum know, those things were made primarily of lead-alloy castings. (I think it had zinc in it - and maybe some other metals as well. Some of the bigger 1/500 ones had wood hulls.) The notable exceptions were a box full of 1/500 merchant ships. When I got that box off the shelf in the storeroom, the first thing I noticed was an overwhelming smell of vinegar. When I opened the box, I discovered that those particular models had been cast in some primitive form of plastic, which was leeching an oily substance that was the source of the odor. What was left of the ships had assumed the shapes of bananas. We gave up on them.
The lead models were in considerably better shape, but many of them were showing the telltale signs of white "flowering." We got on the phone with a professional conservator, who advised us to try electrolytic reduction. We set up an electrolytic reduction tank, made from a plastic bucket, a battery charger, a piece of stainless steel, and a solution of sodium carbonate (from a swimming pool supply company) and water. We stripped the original paint off the models and gave them the treatment for the prescribed amount of time. Without exception, when they came out of the tank they looked beautiful. We gave each of them a coat of primer, followed by a finished coat of acrylic paint (Poly-S), then wrapped them carefully in acid-free paper and stored them in metal cabinets (rather than the original painted plywood boxes), with plenty of air circulation. The lead disease was back within six months. Shortly thereafter I left the museum; I don't know what, if anything, has happened to those models since.
The other experience had to do with a most interesting model of a late-nineteenth-century German merchant ship. Its owner, a Navy attorney, brought it to the museum one day in the hope of finding somebody who could restore it for him. Needing money (as usual), I took it home with me; it was one of the more interesting and worthwhile model restoration jobs I've undertaken. The model obviously had been built by a sailor, and, though the details of course were pretty crude in some respects, it had all sorts of interesting and unusual features that left no doubt that the guy knew what he was doing. Several of the fittings (anchors, carved work, etc.) were made of lead, which was showing signs of flowering. I cleaned them up as best I could, primed them, and painted them.
Some years later the Navy attorney who owned the model retired and, by remarkable coincidence, got a job teaching criminal justice at East Carolina University, where I work. A few years ago he called me on the phone and asked me to come take a look at the old model; he said some white paint was chipping off it. (This was a pleasant and fascinating exercise. A conservator rarely gets the opportunity to work on an artifact at intervals of twenty years.) Sure enough, it wasn't white paint; it was lead disease. The model had been living in a more-or-less airtight plexiglas case, sitting in a window where sunlight hit it for several hours each day.
Once I got the "flowering" brushed off, the original lead parts didn't look too bad. After discussing the problem at length with the owner, I decided to clean them up, reprime and repaint them, and leave them in place. (One of the basic principles of artifact conservation is to replace original components only when absolutely necessary.) The owner was happy with the result - and got a new, glass case for the model, which he now keeps well out of the sun's reach. If the lead disease shows up again he's to call me again and we'll consider a new strategy. All that took place about five years ago. So far, so good.
My observation has been that lead disease, in the context of ship models at any rate, is utterly unpredictable. I suspect that's partly because the "lead" used in models actually has other metals mixed in with it - in inconsistent amounts. The environment in which it's stored also seems to be a factor; the combination of plexiglas, a relatively airtight enclosure, and sunlight almost guarantees disaster, but in other circumstances lead castings sometimes look pristine after decades - and sometimes start deteriorating visibly in a matter of months. (I've seen ship and railroad model kits in hobby shops whose lead parts started flowering before they got sold.) Nowadays, fortunately, the manufacturers rarely if ever use lead. Neither do I. It just doesn't make sense, when so many other, more durable materials are available, to take the risk.