My cordless drill has been sitting on the shelf, useless, because the batteries are dead. Not anymore...I replaced the internal batteries with ones that were a higher quality and longer lasting! Others have suggested zapping NiCad batteries with high current...this may work, but also runs the risk of damaging any internal circuitry the battery may have, and could cause the batteries to explode and spray hot/toxic chemicals over you! It's also only a short term solution. This is a safer method with a guaranteed outcome, and a great upgrade. If you're on a very tight budget and have shorted NiCd cells, you can isolate the bad cells with a multimeter and just replace the bad individual cells.
1) Soldering equipment
2) Small heat shrink tubing (optional, if your battery pack requires splicing)
3) Large heat shrink tubing (optional, if your battery pack has a temp sensor)
4) Correct screwdriver bits for disassembling the battery case
5) New replacement batteries (see step 2 for help)
In theory this can be done to just about any item that uses rechargeable batteries, but results may vary depending on many factors. Do not attempt this unless you are confident soldering and working with high power electrical circuitry - many of these batteries pack a mean punch, especially when assembled! NOTE: they carry enough current to weld in some cases. In this example I will be using the battery from a Craftsman Professional 9.6v Cordless Drill, item # 9614 or 11030.
NOTE: This was the first time I've used a very old camera and I did not realize that the pictures were not great until after the project was over...please let me know if you need more pictures or info!