Today I have by accident thrown a AAA battery into a bucket of water. I fished it out of the water immediately (within 20 seconds or so) and nothing notable had happened and the battery is still full according to a battery test device.
Cats Scratching Ears with Parasites. If this is not the issue, then it may be related to parasites alone. Check your cat's ears for signs of ticks, fleas, and mites. These parasites can cause obsessive scratching, as the cat makes a desperate effort to relieve pain and discomfort. If your cat is not allergic, try using natural tick or flea repellents (or mite repellent) if that seems to be the issue.
If your cat has ear mites, your dog or other pets will likely have them as well. In pet shops, catteries or shelters, where cats live in close proximity, ear mites are a common problem. A cat with ear mites, distressed by the itching they cause, will shake his head and scratch at his ears vigorously. He may scratch so hard that his ears will bleed or blood vessels may break. Ear mites can cause a cat to flatten or tuck his ears back, and the cat may cry if you touch them. His ears will also give off a foul odor.