klossner: This cache was hidden in a little park outside the administrative offices of the local sewage treatment plant. The park features pools of clean water taken from treated sewage -- "chemical soup." Along the paved pathways are light fixtures, about three feet tall, with the reflector pointing down to illuminate the path. A piece of clear thick plastic covers each reflector to protect the lamp, but one piece was mostly broken off. This cache, then, was a magnetic keyholder placed next to the light bulb up inside that fixture. You had to get on the ground and look up to see it.
Today I found that somebody had replaced the plastic cover, but had left the cache in place! See the enclosed photo. I used a screwdriver to open up the enclosure and retrieve the cache.
I couldn't "repair" this cache by breaking the new cover and I couldn't find another suitable hiding place, so it's time to archive this one. Thanks to everybody who hunted it.