Step 1: Amass Gear
Screwdrivers (size and type depend on your particular )
Pliers (you might be able to get away with sockets if your grill is less rusted than mine...)
Corded drill (Yes, you MUST have a corded drill to run the wire cup! Don't even think about trying it with the cordless!)
Degreaser (I used engine degreaser)
High-heat paint (Obtained from the local home center for about $4 per can. I used one.)
Grill cover (You don't want to have to do this again next year!)
Not shown: Grill brush
Cordless drill (I despise turning screws by hand!)
Not shown: Shopvac
Step 2: Disconnect Tank
Step 3: Cleaning Rocks
What? Go buy new ones? Are you nuts? There's plenty of life left in these!
Note to those with lava rocks: Don't try to scrub them, it'll only make you batty. Go buy new rocks. Or if you live in Hawaii or some other volcanic region go collect your own, but don't tell them I sent you. (To those who will inevitably bring up that collecting lava rocks is illegal in some locales, I say collect elsewhere.)
Step 4: Degrease It!
Disclaimer: Be sure to read, understand, and follow all the safety rules that come with your degreaser. Knowing how to use your degreaser properly will greatly reduce the risk of personal injury. And remember this: There is no more important safety rule when you're working with degreaser than to wear safety glasses.
Step 5: Pop Out Thermometer
While you're at it take off the handle, too. (Sorry, no pic.)
Step 6: Pull Out the Burner Unit
On the underbelly of the grill are four screws holding the burner unit down. Now would be a great time to remove them. Unfortunately, mine were so rusted that they wouldn't spin. Fortunately, they were so rusted that when I lifted the burner unit up and the material around the screw crumbled enough that I didn't need to unscrew them.
I don't think this grill will be lasting for more than another year or two...
With the burner unit now unattached, lift it straight up while sliding it towards the back of the grill. This will free the burner unit's feed tubes from the control unit. Now lift the burner unit up while rotating it towards you, which will pull the feed tubes out of the hole they are in.
Step 7: Remove the Control Panel
Pulling the knobs off reveals two screws. Unscrew them and the control unit should come right out.
While you're at it, unscrew the nut behind the igniter button and pull it out, too. I had to pull the igniter lead out of the button in order to get the button out of the front panel. It's supposed to come apart like that though, so don't worry.
Step 8: Gunk Removal
Note: If you tip the grill over to knock the gunk out, you might want to take the lid off first, as shown in the next step.
Step 9: Decapitation!
Step 10: A Little Bump and Grind
Do I need to do the "be safe when using power tools" disclaimer? Well, be safe when using power tools, mmkay?
Using the wire cup and firm pressure, scrub all of that rust off! I did what I figure was an 80% removal--it would have taken more time than I had to spend in order to remove 100%, but I got all the big stuff and most of the little stuff. Anyways, I felt good about it.
When you've got off all the rust you can get, you might consider sanding with some wet/dry sandpaper. That's up to you...but if you're going for the "just try hold in there for another few years" approach like I was, you will probably skip the sandpaper part.
Step 11: Say It, Don't Spray It!
I didn't paint the interior because 1) I knew it'd just be greasy again within a week and 2) I was running out of time.
Spray according to the directions on the paint. Mine said make several light coats a few minutes apart, dry to the touch in 1/2 an hour, ready for heat in an hour.
Step 12: Reassemble
Start with the lid. Add the handle and the thermometer.
Screw in the control unit and the starter switch. Press on the control knobs. Put the burner unit back in and screw it in (if there's anything left to screw it in to). Arrange the igniter so that it is either a) back where it came from or b) close enough that it'll ignite the gas quickly.
Gently drop in the bottom grate. Add the now-clean briquettes in any kind of pattern you care to use. I chose a boring grid pattern. Place the cooking grates back on.
Hook the back up and check for leaks according to the manufacturer's instructions. Light it up, just to make sure it's all working. When it's cool, put on your nice new cover!