Why shouldn't I use acid or heat to test a rock?
Acid and heat are genuinely dangerous outside a laboratory, they rarely tell an amateur anything useful, and they can permanently damage a meteorite's scientific and collecting value.
You will sometimes see advice online to drop acid on a suspected meteorite, or to heat it with a blowtorch to see what happens. Please don't, for three reasons: your safety, the rock's value, and the fact that these tests do not actually answer the question.
Safety comes first. Strong acids burn skin and eyes and give off harmful fumes, and some react with metals to release flammable or toxic gases. Heating rocks is risky too: trapped moisture can turn to steam and make a stone crack or burst, flinging hot fragments. Neither belongs on a kitchen table, and children should never try them.
The second reason is damage. A meteorite's outer fusion crust, the thin dark skin formed as it plunged through the atmosphere, is one of the most important clues to its identity, and acid or heat can destroy it. Heating also changes the minerals inside, alters the magnetic properties and can reset the records scientists use to study a meteorite's history. A specimen that has been burned or etched by an amateur may be far less useful for research, and much less appealing to a museum or collector.
Finally, the results mislead. Many Earth rocks fizz in acid, and many meteorites do not. Heating a rock tells you nothing that a specialist cannot learn far better with a microscope and laboratory analysis. Professionals do use acid in controlled conditions, for example to etch a polished slice of iron meteorite and reveal its crystal pattern, but that comes after the meteorite has been identified, and with proper protective equipment. Safe first checks include looking for a fusion crust, testing whether a magnet is attracted, noting whether the rock feels unusually heavy, and photographing it. Then contact a museum, university geology department or meteorite specialist, who can confirm it without harming the specimen.