Yes
Nothing it will not harm the battery at all. It is sealed from outside elements. I do not mean putting it under the water as that would short it out. But to rinse it off is fine.
Your putting a charge on the battery when its running.
by putting a battery
No. Water will not burn, although the hydrogen and oxygen that make it up are both highly flammable. It is possible that putting a battery in water could create those gases by electrolysis under some conditions.
There is no fool proof way. Get a new battery if putting it on a slow charger does not work.
No. That would defy the point of putting the battery there in the first place.
battery water is distilled water
No. It does not require very much power. If the battery is not putting out enough power to turn the starter, but is putting out some power it may still work. If the battery is totally dead it will not work.
Use distilled water. If the battery is a sealed battery you cannot add any water.
No unless you leave it in there for months. Want to drain it, the connect something to the battery and leave it on.
try turning it off then removing the battery then putting the battery back in the turning it on. it worked on mine