It really depends on how far the liquid damage extends. If it made it to the logic board, then odds are it's going to slowly, but surely, corrode it. You won't really know until you open it up and look, but it sounds like it might be contained to just the top case. I'm assuming you have a unibody model without a removable battery.
There's a fairly easy way to test that, if you feel comfortable enough taking the bottom case off and tinkering with a few components. Once you remove the bottom case, if you look by the battery, you should see a flat ribbon-like cable. CAREFULLY use your fingernail to pull up the locking bar, then work that cable out with your fingers or a plastic piece. Disconnect the battery, and then you'll need a flathead screwdriver. It's hard to describe where to look exactly, but if you google MacBook unibody power pads you'll probably find a few photos. Otherwise, look for a couple of white squares a bit to the left of the cable you just disconnected. There'll be more than one set, so just use the screwdriver to try and short each set until the unit turns on (you'll need the AC adapter connected naturally). IIRC, they should be in kind of a vertical orientation, but it's just kind of one of those things you stop thinking about once you've done it a few dozen times like I have. If the unit powers on and boots all the way into the OS, then you have a top case with a stuck power button, and there's at least a chance you could find some AASP in your area willing to replace JUST the top case. Believe me, you really don't want to attempt that one on your own without the proper tools. The display assy has to be put on at a particular angle. If the thing still keeps shutting off, sell it on ebay for parts.
Just don't try any of the things you listed or you're probably just going to make matters worse.
After a white wine spill on the keyboard, the computer stopped. My wife mistakenly tried to restart it, several times, and never disconnected the battery. Brought it to Apple, they quoted a price to fix, so she just bought a new one. Two weeks later I get it and, assuming it's the logic board, try most of the tricks I've read online (scrub logic board with alcohol, blast with electronic contact cleaner, even bake in the oven (380 degrees, 7.5 minutes)). At start up the fan works, the screen lights up, you see the apple and the thing going in circles, but no chime, and it shuts off after 10 or so seconds. Any other suggestions on trying to get the board to work? It may be toast, but I'm willing to try again if there's a reasonable remedy.