Safely discharging CRT monitors

Author: Nick (and one other contributor)

IMPORTANT: CRT MONITORS CAN HOLD ANYWHERE BETWEEN 15K VOLTS (small B&W)-25k VOLTS (small-medium color), UP TO 50K (TVs, studio monitors, high-end desktop monitors like the GDM-FW900). DUE TO THE WIDE VARIATIONS OF WHAT EACH TYPE CAN HOLD IT IS CRITICAL THESE GET DISCHARGED CORRECTLY!

This Wiki intends to bridge the information from this answer made in 2018 and expand on this topic further, and make the format better suited to be used in the field. This post was made as the age of the answer most of this information was in has aged to a point it is hard to locate: Disassembling an old Apple monitor. In addition to this answer and post, refer to this Apple document: CRT Safety.

The first rule to safely discharging a CRT monitor is to make sure the monitor or computer is unplugged; this is to prevent further charge from coming back. In addition to this IF possible either flip the power switch on for 30 seconds, up to 1 minute (or hold the power button) to discharge the monitor. This may very well be enough for modern "bleeder-based" CRTs with a working bleeder resistor but CRT discharge is silent and does not give itself away; as such, you need to physically discharge the display to make sure it has been fully discharged. As these resistors take a lot of abuse and can fail from being exposed to such voltages within a few years, you still need to manually discharge CRTs to make sure it is safe to work on.

IMPORTANT: DO NOT WEAR ANY GROUNDING STRAPS; ELECTRICITY CHOOSES THE PATH OF LEAST RESISTANCE AND YOUR ESD PROTECTION WILL BECOME THE GROUND. As such, you must remove all jewelry (and items like necklaces) even if doesn't have metal to be sure you do not become the discharge ground.

After making sure you do not become a "ground", it is time to work on discharging the CRT. You can do this with an official discharge tool (which was made for companies like Apple for service purposes) or an open-market tool that was sold to everyone. However, these are no longer in production and are extremely rare (if not unobtainable today). As such we now need to improvise; you can use a plastic-handled screwdriver with a rubber grip and most will work, but you want to make sure you are (ideally) using a screwdriver with rubber+plasic isolation if possible.

While it isn't a strict requirement the risk of death/injury from a CRT greatly outweighs the costs to get a proper screwdriver. These can be found at places like Home Depot or Lowes. These will cost significantly more than a plastic handle driver but are properly insulated. It is advisable to insulate part of the screwdriver handle with heatshrink tubing if you can do so to create an area for additional protection; this is meant to act as an insulation cushion if you miss, so caution must still be taken. Refer to this guide for a visual aid on the discharge process: Macintosh Classic II Power Board Removal
If you can locate the tool, this is generally what they look like (Apple-made version) although other versions also were made by other companies that serve the same purpose:

IMPORTANT: WHEN DISCHARGING THE CRT ITSELF DO NOT HAVE BOTH HANDS IN THE WORKSPACE! IF BOTH HANDS ARE IN THE SPACE THIS CAN CREATE A DIRECT SHORT TO YOUR HEART WHICH CAN KILL YOU. Put one hand behind your back or a pocket to make sure you do not create a complete circuit. Remember: It is better to drop a loud F-bomb your neighbor can hear with one hand in your pocket instead of being dead... Once you hear the CRT make a "crack" sound, this means the CRT has been discharged.