[Andrew B]

A while ago I was >harvesting< the zinc from exhausted cells picked out of the supermarket "recycle". I wanted the zinc to use as kathode/anode electroplate a couple of engine mounts.

I pulled out a few of the big 6 volt lantern cells (good zinc sources) and also found some "D" sized zinc chloride cells. The "D" cells did NOT have a zinc outer, after stripping them down I found they had a thin zinc coating on the inside of the steel outer case, I figured that when the battery was getting low on zinc, the chemicals inside would just eat through the thin steel casing in no time.

I found that PP3 batteries come in 2 flavours, one type contains pile cells and the other type has 6 "AAAA" cells inside.