Basically what you want to do is use Nail Polish Remover, Set the battery upside down in a tubber ware and fill up about a 1/4 inch past the seam,

let it soak for about 4 hours... ( this i did not do ) i was impatient, finished with a dremel.

you can see the seam that i did let it soak some and it came right apart with the twist of a flat head.

Anyways I found a good replacement, It's 6v and 5.0 AH, Fits nicly!

19.99 at batteries plus.

Check pictures for exact model #