Question concerning batteries

I realise that this has little to do with computers, but I would not know where else to ask and knowing that this forum is frequently visited by people who seem to have taken an interest in electro-engineering...

1. Why and how do batteries start leaking when they are inserted into a device that has not been on for a certain amount of time?

2. What would this time period be and by what is it affected?

3. Once a battery starts leaking, is the device considered useless?

4. Once a battery starts leaking, is it wise to simply remove the battery and insert a new one?

5. What do you use to clean the substance that battery leaks? What is the name of the substance?

[Moderator]

This is going off of what I heave heard, but...

(1) The acid just sits in the battery, and eventually eats away at the metal covering.

(2) Anywhere from 1/2 a year  (for cheapies) and after (for the better ones).

(3) The battery is, but all you have to do to the device, is clean it up.

(4) Yes and just toss the old one away.

(5) Not sure....  

[glb]Flame[/glb]

What batteries....are you refering to!

What batteries....are you refering to!

AA/AAA type of batteries. The kind of batteries you would find in flashlights, remotes and other simple devices.

[Moderator]

Yep. That's what I was talking about  

[glb]Flame[/glb]

I agree with Flame, except alkaline batteries don't use acid.
Alkaline battery - Used in common Duracell and Energizer batteries, the electrodes are zinc and manganese-oxide, with an alkaline electrolyte.

http://science.howstuffworks.com/battery.htm