Several years back I built an obs hive or box, which I often take into classrooms. Cleaning plexiglas is difficult to do without requiring a re-polishing of the surface to restore its transparency. I ended up using laminated plate glass (safety glass, or two pieces of glass with a layer of plastic between them, like windshield glass). 

I used a set of rail and stile router bits to build a four piece oak frame around each of the two pieces of glass. The frames are not glued, and in turn each framed piece  of glass fits into a rabbeted  slot on teach face of the box. When it's time to clean the glass pieces the whole thing comes apart, and I can carefully scrape and clean without damaging the glass, which is about 1/4 inch thick.
 
The glass was pricey, perhaps $50. The box is a bit heavy, but so far it's been indestructible. It was in a wagon once, loaded with a brood frame, when the wagon rolled off a curb and toppled onto its side, with no damage to the box or the bees, and no "escapees."

C.Crowell
Hightstown, NJ

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