where to attach the ESD wrist stap's crocodile clip

Hello and happy new year in advance. :)
I have a question here. where would be the suggested spot to attach
the crocodile clip of an Electrostatic discharge (ESD) wrist strap. I
was thinking about attaching the crocodile clip to the exposed metal
of any electrical appliances such as my PC's power supply while its
plug remained on the power receptacle. Would this be working?
.