sorry, but no. You cannot access any date if you cannot access your phone. There is no way to clear anything etc. You will have to try to get it repaired at least to the point of starting up to accomplish this. There is no other way.
Opening the phone and drying out is not enough. The whole board will have to be decontaminated and cleaned. Then you would have to ensure that all components are working by checking for short circuits etc.
You can try and clean it and see if that will yield any result.
The very first thing you want to do is to not try to restart/sync the phone. This may further damage your phone. The next thing to do is to clean it. Disassemble your phone using these guides. You must remove all the EMI shields of the logic board. If you do not remove those you are not cleaning 3/4 of the board. Clean everything with +90% (no less than 90%) isopropyl alcohol. Follow this guide, and even so it was written for an Apple iPhone 3G all the points are still pertinent to your phone. Pay particular attention to the SMD components, check for charred missing or broken missing. You can then dry the board in an oven or equivalent at 220deg F (not higher;-) for a few hours. Best way to clean it would of course be through an ultrasonic cleaner. Consider professional help with that When it is properly cleaned, replace the battery. Once all this is done, reassemble your phone and reevaluate.