Light microscope bulbs get very hot and some can have hazardous waste issues? 

Users should be aware that when they need to replace a freshly burned out microscope lamp bulb, the old bulb can still be very hot! It is always best to wait until the bulb has cooled before removing it. Handling a hot bulb requires heat-resistant gloves and eye protection, especially since Mercury and Xenon bulbs can explode when hot.

Install any type of new microscope bulb (arc lamps, halogen, metal halide) by handling the bulb with cotton gloves, a kimwipe, or powder-free gloves to avoid depositing finger oils on the lamp surface. Once the bulb is turned on the finger oils can weaken the glass, increasing the possibility of the bulb shattering.

Arc lamps (e.g., for fluorescence) often have a preferred orientation in the housing. To be sure you install the arc lamp bulb correctly, check the documentation, or ask your vendor’s sales representative to show you how to install/align the bulb. If you need to replace a bulb immediately and you don’t have the necessary information, try to install the bulb in the exact same orientation as the old bulb (this assumes that the last person to replace the bulb installed it correctly). Incorrectly installed microscope bulbs can change the alignment of the illumination, which may result in uneven illumination which can be seen using the eyepieces or camera.

Note: Mercury bulbs should be placed in a zip-lock bag, tagged for UA Risk management, and they will be collected when your lab has its regular HazMat pick-up.