grounding/earthing

Not sure where best to post this question....

How do you earth/ground a computer to make it safe to delve inside it?

Just asking, as ours seems to get mega dusty very quickly, but im a bit worried about opening it up!
My husband has gone right inside it before to give it a really good hoover, but i don't think i could take the stress anymore as its so dodgy!

Just the usual precautions. Make sure the mains is unplugged. I usualy earth myself on the kitchen stainless steel sink and work very gently inside the case. It's mostly common sense