Happily, the MacBook isn't very hard to take apart. Also, since we could afford to replace it, we had two over the Thanksgiving break, and could determine that there were no MagSafe power cord or battery issues.
You can see a nice MacWorld video of the basics of opening the battery bay, removing RAM and Disk Drive.
The disk and memory chips were gunked with month-old coffee crud. A scrub with a soft, cotton towel and plain water got through a lot of it. Then we started into alcohol, using medical alcohol wipes so we could scrub without leaving a lot of linty residue.
The memory chips were simply scrubbed with alcohol until the contacts were clean-looking.
The serial ATA hard drive is enclosed in a metal shroud, held on with four #8 Torx connectors. Under this was a circuit board with coffee stains. It, too, got a thorough scrubbing.
Phase Two.
After cleaning the accessible parts, we have to move into the guts of the machine. The Kodawarisan site had a great sequence of photos. There are innumerable internal screws of at least four different styles: very small, small, small with a little barrel, and long-ish. All have to be kept separate.
It's hard to get a good screwdriver angle on these things. Radio Shack carries a Kronus ratchet set with the necessary Phillips and Torx heads. This helps to break the screws loose without stripping them. Once loose, an ordinary precision screwdriver works well.
Once all the internal screws have been removed, the external screws come out. They're all readily accessible, but come in many shapes and sizes. There are two lengths on the bottom, really short ones on the left side, barrel screws on the right side, and a mixture of mid-length and barrel-style on the back. Keep them all separate. A piece of paper with labels for the various sizes and their locations is a big help.
Lifting the Lid.
The keyboard doesn't lift out too gracefully. The left side lifts a little more easily than the right. However, there's this really important piece of ribbon cable from the main circuit board to the back side of the keyboard. While wiggling things around trying to get a good look at this, it dropped out of it's socket.
Around the DVD drive are a number of very small plastic clips that keep the keyboard and case all nicely aligned. These are prone to slipping out of position. Don't loose these, and don't let them go astray. These are critical to keeping the DVD slot and DVD reader aligned correctly.
Lather. Rinse. Repeat.
A number of web sites indicate that isopropyl rubbing alcohol works well for cleaning circuit boards. However, we need to remove coffee, and we can't really get at the board with much more than a swab and baby toothbrush.
I tried a swab with alcohol, followed by scrubbing with the baby toothbrush and found that this works well. I inspected just about every visible IC component for crud, moving across the board from top-left to bottom right. After a half-hour of squinting through a hand-lens, we took a break, and returned after our eyeballs relaxed. Another half-hour of squinting, swabbing and scrubbing left the board looking acceptable.
It didn't look new, but it was also free from visible coffee stains. Some of the contacts were discolored, but the crud was removed.
Test Drive.
For a test drive, I held the keyboard in place, plugged in the power, and hit the power switch. After being dead for months, it recovered to where it was when my daughter filled it with mocha java. I was amazed.
I did a nice, controlled shutdown and started putting screws back in. There are a lot of them, and they are small. Also, parts of the interior are magnetic, so the screws don't behave well.
False Hope.
Above, I noted that a number of small, plastic clips keep the keyboard and case nicely aligned. If these aren't in position, the DVD slot doesn't line up with the DVD drive. After I reassembled everything, I had a part left over and an ugly lump near the DVD drive slot.
I booted and ran through the software upgrades she hadn't done. When that was finished, I took it all apart again. I reseated the clips, and things went together much better the second time around.
The DVD that had been in there still wouldn't come out. To get it out, I had to pull the slot open with just a fingernail on each side. Once the slot was clear I did the following.
NOTE. You may not want to do this, it sounds dangerous. It probably is. You might break something. You have been warned.
I put a small Phillips-head screwdriver into the DVD slot and wiggled it to seat everything correctly. Since there are delicate parts in there, I only put the screwdriver in about 1/4" or less. Wiggling the drive up and down in the slot seemed to get it seated more squarely behind the slot.
Victory.
The MacBook seems to run just fine. We'll resynch the files and send her back to school with the coffee-stained machine. The like-new replacement will go to someone who needs a new computer: my son.