I got several replies on how to remove the crystalline corrosion in the device when small batteries go bad. One was alcohol, and since I had some on hand, tried that first. Didn't really dissolve the crystals, but softened them up enough that I could get them off with a pocket knife, then clean it up with more alcohol on a Q-tip. Put in new batteries, got nothin'. Fussed around a little more, got a very weak light (this is in a laser level). Got called away to the phone, and when I came back in about 5 minutes, laser was as bright as new. So the lesson is, don't give up too soon- maybe it takes a few electrons running around for awhile to get things back to normal. The other lesson, of course, is to take batteries out- but we all have a zillion little things with batteries in them, so that's going to be a tall task.
Thanks to all who replied.
Thanks to all who replied.
