Just don't charge them with the built in charger, if it has one; always use a proper NiMh charger.Every now and then you do find a device that doesn't like NiMH cells. The usual reason is the lower full-charge voltage, 1.2V vs. alkaline or carbon-zinc's 1.5V. A device with a battery charge meter will often claim the NiMH batteries are at 75% or so when they're fully charged. In practice the voltage of alkaline or CZn drops to close to a volt very early in its discharge curve, so modern NiMH cells will run the device for about as long, or longer.
If you do run into a problem device like this, you can get rechargeable alkalines. They do require a special charger, but they have a "fully charged" voltage of 1.5V. They're not as good as NiMH all around, but they do solve this one particular problem.
(Rated by 1 Council Member)