Removing the Power Supply? Handling, discharging, avoiding shock...

So I'm parting out an Intel iMac 17" to sell the internal components to those that need it (LCD is broken; too rare and expensive, don't want to deal with it).

Anyhow, I've successfully taken out the logic board with the iFixit guide. I want to remove the power supply and put it in a small box to store it away, but I'm really hesitant on bringing my hands anywhere near it.

I know that capacitors can hold a charge and shock you, and after one experience I had on a project with a disposable camera, I figure that the PSU must hurt a lot more. Does the charge dissipate over time? I've had the iMac disconnected from the mains the entire time during disassembly after testing the parts.

Sorry if this is a silly question, but I'd rather be safe than sorry.