You have to take the MBA apart (download and view instructions from net).
Get PURIFIED water, distilled or reverse osmosis. NOT spring wather or one with added minerals.
RINSE all the parts, EXCEPT the HDD.
With the HDD there is a small vent hole. Tape that closed and give the circut board a quick rinse.
**GOAL is to remove all the salts and chlorine from the electronics.**
Use a HAIRDRYER to dry off the parts. TAKE YOUR TIME.
When all visible water is gone, set a fan on the parts and let it blow over parts for another 24 hours.
I am 99% confident everything but the HDD will work just fine (rescued 2 iPods and 2 computers this method)
For the HDD, best get an external case and hook that way, see if it will start up.
1 HDD I had that was water damaged did work, but make a horrible noise (I think the bearings rusted, not sure). Was able to take all the data out, and stopped using it.
Hope it helps