I use to have an insulated screwdriver where the entire length of the shaft, about 1 foot, was insulated except for the tip and at the handle there was a very heavy wire, about 20 inches long, with a huge alligator clip on it for connecting to ground. The handle appeared to be doubled insulated.
It was great for discharging caps but I never used it for PSU's over 1KV... When I made supplies of 1KV or higher I had huge dropping resistors that would kick in on time delay relays to discharge the caps when the unit powered down. Also I used sequencers on power up slowly... in some cases I would use variacs for power up. The variacs came in handy for gear that I just picked up and was questionable for operation. I considered everything that came in as "questionable" in quality...
And don't get the idea that it is just high voltage that can be dangerous I had a 24 volt supply that had a current output of 50 amps... It had 10 @ 100,000 MF caps in parallel and that thing tossed a pair of vise grips that got dropped accidentally on the caps connecting straps and it flew 5 feet into the air and stuck in the ceiling of my lab... It sounded like a 12 ga shot gun blast...
Point is... use great care with any PSU... never take anything for granted... EVER!
Have a great and safe New Year...