Honestly, Waragainstsleep, just stated how to do it. Its actually very easy. However, and I'll say this again, when working on an emac, it is usually unnecessary. The CRT and the analog video board are shipped by apple as a complete assembly. you remove the housing, and depending on the model, maybe the speaker assembly. You pull off the back grille and remove the logic board/drive assembly, and you're left with the analog display assembly, held to the front bezel with less than a dozen screws around the edges. You remove those screws, and you can pick up the display assembly by the plastic hoops on either side. Then you set it aside.  You've just taken apart an eMac.

Now, lets assume you want to dig into the analog display assembly. then you DO want to discharge the CRT. I'll explain in detail.

1. find a flat blade screwdriver.
2. find a piece of wire with alligator clips on both ends.
3. clip one end to the screwdriver.
4. clip one end to the heat sink on the assembly, or to the metal framing.
5. make damned sure you arent wearing a wrist strap.
6. on the back of the CRT, look for the large black suction cup thing, that has a wire sticking out of it.
7. pry it off with the screwdriver.
8 rub the cap's contacts with the screwdriver
9. look at the CRT. see the inverted nipple in the glass? thats the aperture. carefully place the screwdriver against the metal ring thats embedded in the glass, and rub it around in the aperture. It may spark, it may not. It will most likely be very anticlimactic. However, you've just bled out the charge. If you set your work aside for a bit, discharge the anode aperture again.
10. when done, and reassembling, pull back the anode cap with your fingers, so you can see the attachment prongs. seat one, and then use the screwdriver with wire to press the other in place. Then let go of the cap, and it will flip back into place.

If you've done all this correctly, you should 1. have removed an anode cap and discharged a CRT. 2. you should have gotten your work done, and replaced the anode cap back into the aperture. 3. you should still be alive, unelectrocuted.

Mind you, when you get tested for Apple's desktop certification, they test you specifically on ESD (electro static discharge). There are 12 questions. if you dont get a majority of them right, you automatically fail. Why? Stupidity with electricity can KILL you. Mind you, this procedure is easy, and I've done it countless times. However, its one of those things you should always pay attention when doing. The last thing your girlfriend, mom, etc wants to find, is you slumped over a half finished project, dead, having vented your bowels into your pants. So yeah, be smart, not stupid smile
Electricity tastes good. No, seriously.