Anti static strap on fully painted case

[ivanteng880]

Hi, I just got into PC building and I got a ifixit pro tech tool kit and it came with a anti static wrist strap. I googled how to use it can they said I have to clamp to alligator clamp on the bare metal part of the PC case. But I have a cooler master H500P mesh and it doesn’t have any bare metal on it. And I googled that and I heard people say that I can clamp it on the PSU screw. But there is only one problem. Both the psu screw from the case and the PSU it self have black screws so I assume that they’re painted. And my friend told me that if I don’t clamp it on to the bare metal of the case, I’m not grounded. What should I do? 

 

BTW I know how to use a Anti static wrist strap. (People from my last forum keep telling me to put it on bare metal)

 

and i I don’t want to die so I won’t put it on the fan grill. Thank you