We all know leaking alkaline batteries can wreak havoc on everything in electronic devices from the circuit boards to the plastic and metal parts. But did you know different plastics react very differently to corrosive battery material?
Most modern plastics like ABS, polypropylene and polyethylene are very robust and clean easily after exposure to leaking batteries. However, older plastics like phenolic resin bakelite (techically polyoxybenzylmethyleneglycolanhydride according to Wikipedia) can react very differently to both alkaline and acidic substances.
In the photo below you can see the inside of a Simpson 260 series 7 multimeter. Even though this model is from the early 1980s, it still uses a phenolic resin case. I had previously thoroughly cleaned it of battery corrosion several weeks prior using alcohol and I think, a bit of Deoxit. Immediately after that it had appeared to be sufficiently cleaned. Obviously, it was not and the corrosive material had continued to react with the bakelite.
Further neutralization was obviously necessary. My usual go-to for this is simple white vinegar. You can see it bubbling away and doing its job below.
After thoroughly cleaning the entire meter with vinegar until no more reaction was noted, it was then rinsed liberally with isopropyl alcohol (IPA) and allowed to dry. As an additional protective step to prevent re-oxidation I applied a very light coating of Deoxit the the affected surfaces.
A final close-up of the worst affected area shows the permanent damage that the leaking battery did to the aged Bakelite plastic. This is a prime example of why batteries should never be left in electronic devices for an extended period of time. Please be kind to your electronics and take out the batteries when not in use!
