I worked on a couple more laptops today with NiMH cells and all of them were in some stage of decay. This kind of corrosion is extremely damaging to PCBs, and it can creep down the wire and onto the board, even if it isn't touching it. I've encountered at least one laptop that was completely destroyed in this way.

The importance of this isn't just about salvaging the battery, but also catching it before it destroys the connector. If you can find a replacement, it's unlikely that you'll be able to reproduce the correct plug end of the cable, which means that you'll have to solder it directly to the board, which often requires the entire motherboard to be removed, which is not a trivial thing in laptops. So, if you do remove the battery in your laptop, be sure to clip off the old connector to preserve it; even if it's corroded and you don't plan to reuse it, it's still useful to help identify which side of the board end is postive and negative for future refurbishment.

Here are photos of the batteries I encountered. There was more damage than this on some of the cables and connectors themselves, but I didn't photograph them prior to cleaning them of corrosion.

You can find more photos of corrosion from laptop CMOS batteries here:

If you own a Sony VAIO PCG-Fxxx series laptop, inspect it for corrosion as soon as possible!

Some photos of the new NiMH button cell battery packs. I clipped the leads off of the old batteries, scraped off and treated any corrosion I found, and soldered them onto new batteries.

I ran out of battery packs for the other laptops I had, so I'll have to set these leads aside until a replacement part arrives.

I still need to remove the battery from my Gateway Solo 2500. It hasn't leaked yet (but it will), and it's only the standby battery (the one that lets you change the main battery without fully shutting the computer down). The CMOS battery is a VL1220 soldered to the motherboard, which I already replaced (Panasonic still makes them, but those rechargeable lithium coin/button cells aren't really available outside of component distributors like Digikey).