from a google search
# Salt Water Method
This could be the slowest method if your battery wasn’t discharged previously by the above methods. Some discourage from using salty water because it’s time consuming, but I personally think it’s a relatively easy and safe solution. No matter what, I always go through this step before dumping my lipo.
The theory behind this is 1 – salty water is electricity conductive and it discharges the battery slowly and completely; 2 – salt causes chemistry reaction with the substances in the lipo battery, and neutralizes the Lithium. I am not a chemist, so I hope someone can verify this theory.
Get a plastic container which you can afford to throw away, and fill it with cold water.
Mix it with salt and make sure it’s dissolved completely. I always use about 30g of salt per litre of water and that has been giving me good result.
Put the battery in the salty water, and leave it somewhere fire proof for two weeks. Depending how much charge it had originally, you might want to leave it longer.
Finally, wrap the battery with paper and it’s ready to be thrown away.
Also note that salt water might not completely discharge your lipo, as corrosion can happen and reduce/stop electrical conductivity (the exposed metal on the leads will have a layer of insulator building up in salt water). Eventually it would slow down, or even stop the discharging completely.