Thanks for telling this.
I always recycle the batteries into the recycle box, everyone should do this.
Because 1 Battery can poison 1 square mitre of soil for xx years ga.
also - for mini z - dont need batterys with high mah, because remember for 電car, you dont what a battery that will last long but you need one that gives better peformance. The intellect 900mah onces are good for this (good choice bearing in mind the cost) Remember the high mah battery are longer lasting but does not provide the top end performance.