I owned a phone store. We "saved" many phones that were dropped into water, soup, toilets ... About the only thing I wouldn't work on was one dropped into ocean water - by the time you get it out of that water, it's too late to do anything but throw the parts out, clean the case and save it as a cheaper replacement case if someone damages the case of the same model phone.
The first thing you do to a wet phone is remove the battery. That means, in a G2, breaking the back open and cutting one of the wires going to the battery. The other choice is a factory reset (if it lasts long enough to do one) and throwing it into the trash - because that's where it's going to end up.
And that's with clean water. Tea? Tannic acid? Which will eventually etch the copper off the mother board? (Not as quickly as etching solution, but a long time before you'd want to get rid of the phone.)
Second step is alcohol - plain old rubbing alcohol. Use it as a "scrub brush", swishing the phone in a bath of it to "scrub" all the chemicals off the parts inside the phone. Do it for at least 2-3 minutes. Drain the phone, change the alcohol (it absorbs water, so what you have now is "wet") and do it again. Then one more time.
THEN put the phone into a jar with about 10 pounds of UNCOOKED rice (or a few pounds of dried silica gel if you have access to any - it works MUCH faster than rice) and leave it for about a week. That will give you about a 50% chance that the phone will survive until it's so old that you want to throw it out.
We'd do one bath (more to absorb most of the water than anything else), then disassemble the phone and actually scrub it with alcohol swabs, toothpicks and a bottle of alcohol. Soak it, scrub a little spot, flush that spot, move on to the next spot, etc. Then 2 more baths and put all the parts into a tub of silica gel for a couple of days.
Leaving the battery in a wet phone causes current to flow where it's not supposed to (across wet places), causing damage. The chemicals in the water slowly erode the phone. Even if you dry it, every humid day wets them again, causing more erosion (and corrosion).
I recently replaced my older phones and wanted top-of-the-line phones. The LG was out of the running as soon as I saw "non-replaceable battery". (I can remove the back and replace it, but it's so much easier to just pop a removable top off and lift the battery out, than unscrewing the case, unsoldering the wires, etc.) But replacing a broken back and having the battery wire resoldered is still A LOT cheaper than replacing the phone - which you're going to be doing soon if you don't have insurance that covers water damage.
No phone is ever completely off - some circuits have to be live so that pressing the power button turns the phone on. (It's a momentary switch, not like a light switch in a wall. Press and it makes contact, let go and it loses contact.) But turning the phone on to "try it" causes even more damage. (Really want to destroy it? Charge it. Then throw it out.)
Sorry, but at this point, your choices are limited (unless, as I said, your insurance covers water damage). Use it until it dies (which, if you're lucky, will be about a week). Take it to a repair shop and get a repair estimate - if you can find a shop willing to work on a water-damaged phone that's been used since it got wet. Use it till it dies, then get a repair estimate. But I think you'll find that an honest shop won't repair it because the cost of the repair will be higher than the outright purchase price of a new phone. (A dishonest shop might replace the battery, charge you for that, then "repair" the screen and charge you for that, then "repair" ... etc., and you're already a few hundred dollars into repairing the phone, so you won't just throw it away and get a new one. Until they tell you that they've done all they can, and that if replacing all the parts (which, if you'll really read the "estimate", assuming they even give you anything in writing, is all they're promising to do - replace parts until, and if, they get it working) won't get it working, they can't help you. And you'll have paid about 1-1/2 times the price of a new phone.
My advice? Bite the bullet. Buy a phone (make sure it's one that you can snap the back off and remove the battery in a second or two). Be more careful in the future. If you can't be careful, see if you can find insurance that covers water damage.
