Try and get the case open if its not a rechargeable battery and therefore a sealed unit.
Car key through washing machine. Use a circult board cleaning spray to displace all water in the key and allow to dry. Shake out as much water as you can and then buff the fob dry with a clean cloth. Pop the battery back in and cover on.
Your best option is to open up the key fob -it will prise open with a knife or some such blace and physically dry it out - Remove the battery and dry around that area too - but dont waste any time doing it - You may already have a problem with the key because of the water - but if the battery is out for too long it loses its coding. Do not use hairdryer or clothes dryer coz the static built up will kill the chip. Aqua Fina is totally pure water.
I was able to fix it by opening the shell and removing all the contents. 14 Jul 11 2019. Hi Ive been a bit of an idiot and managed to put the key for my Mk 4 Golf GTI through the washing machine.
Use your good key as the master key and follow this here. This is the only way to get all the minerals. I can start the car by putting the fob in the center console transmitter pocket but the remot.
In the meantime do not use the key ie press any buttons. To assemble Pop the circult board back in. Even if you got a new key.
All the other cars I currently have are standard key locks only no remote entry so I had TRIED to be careful with the Smarts key just in case I forgot. As I mentioned it didnt go through the whole. If not buy a jug of distilled water zero minerals bathe the fob in it and repeat the drying process.