I had some experience with liquid spills: water, wine, screen cleaner, etc.
In addition to all what was written above, I would add:
- Go about it slowly. Don't generalize, due to the so many places liquids can seep into and the extensive list of reactions, shorts, and damage they can cause.
- Some means that seem extreme can be used when nothing else works and you have nothing to loose. Just do it gently and don't force it.
- If it's working at first, and starts "working less," then stops working, it usually is due to corrosion.
- If a whole "unit" is not working instead of parts of that unit (example: some key vs. the whole keyboard, or 1 button vs. the whole trackpad), it can be useful to look at the gate e.g. connectors and sockets for those connectors.
- Completely dead is usually easier to fix than part dead, speaking from the experience I've had. Have faith :)
I'll illustrate with a few examples:
- An unusual fix? I had a Vaio trackpad with coffee spilled in it, that wouldn't work. It was sandwiched between two layers of glued/fused thin plastic and couldn't be removed without breaking the plastic layers. Before breaking it apart, I sprayed some WD40 a few times, let it soak then drain out over the course of a couple of hours, and it worked since. 1 year now and no complaints from this now happy return customer.
- Works than stops working / corrosion: a client brought a MPB drenched with water, for us to have a look. Another service center had quoted $900 the cost of replacing the mother board.
At first the MBP "mostly" worked fine apart from the HDD which was clicking (due to a drop that happened before the water damage). Some keys from the keyboard that were not functioning after the spill. Corrosion marks and liquid marks were all over the motherboard and the inside of the case.
By the time I was able to work on it the 2nd day, the trackpad had stopped responding whereas it was working before. Then the MBP wouldn't start. I deduced that corrosion was eating away at the board and the connections between the MB, the on/off button, and the trackpad. Cleaning them with contact spray & isopropyl alcohol did not solve it. So I sprayed WD40, and very gently scrubbed the corrosion on the board and the tip of the connecting flat cables, using a used/soft toothbrush to avoid damaging any solder joints. Those may have become fragile due to corrosion. As a result everything worked again except some keys on the top case which had to be replaced. The repair ended up costing less than $400, including our fee, the cost of the HDD and a replacement original top case.
- Part vs. full dead: a new mid-2013 MBA was brought to us after the owner spilled wine on the keyboard. The keyboard and trackpad were both completely dead/unresponsive. It was weird because usually a spill would kill some keys on the keyboard and not ALL the keyboard would become unresponsive.
I was still unfamiliar with this model, so I used a guide from iFixit to take it apart and study the insides. I noticed that unlike previous models of MBPs that I had worked with, this MBA had a flat cable connecting the motherboard to the trackpad, then another cable connecting the trackpad to the top case: so no direct connection from the top case to the motherboard. And no traces of corrosion anywhere, just some spill marks on the trackpad, the connecting flat cable, and its socket.
I cleaned everything with isopropyl alcohol while scrubbing ever slightly, but no luck..
I examined the cable using my 20x scope, and found the culprit: the electrolytes from the liquid, combined with the electric current traveling through the cable caused the gold or copper on the tip of the cable to migrate from one pin to the other. Now all the pins connected and caused the cable to short. This issue was not apparent to the bare eye. Looking through the scope, I used a needle (nothing thicker would do) to scrap the metal between the pins to remove the short. I put everything back together and the MBA worked like a charm. All the keys on the keyboard also worked perfectly. This guy was lucky. I gave him back his laptop and ordered a replacement cable since I figured this one was a bit "diminished" and needed to be changed later on. But the owner has yet to come back and have it replaced :)