+1 @erik_squires .
I am not an electrician, but thanks to the seniority bump & bid system I did a few tours through the electric shop of a major airline. We used what I remember being called a "shunt" to discharge all caps. (It is possible I remembered the terminology wrong.) But basically it was a wire with a probe on each end and a resistor soldered in the wire (obviously between the two probes). What everyone did, so therefore what I did, was when working on something with caps involved was, put one probe on one lead of the cap and the other probe on the other lead of the cap, and that would discharge it. I did just dig out the "shunt" that I took home and kept for my own use and measured the resistance, and I read 123.8 ohms on it.
Once just for the helluvit, I decided to check the caps on an old preamp that I have, and for that I used this handy-dandy cap checker from China that I bought on Amazon. However, I forgot to discharge the cap I was checking first. The cap did discharge, but it cost me my handy-dandy cap checker.