Distinguish between hydrochloric acid and aqua regia: If we wash gold, we must pay attention to the routines of merchants. Although gold and platinum can be dissolved in aqua regia, the dissolution speed is slow and difficult to detect, so we can distinguish aqua regia from hydrochloric acid.
1, the two colors are different. Hydrochloric acid is colorless and transparent, but it turns yellow when it comes into contact with air. Aqua regia is yellow-green at first, but it will turn yellow-red after being dissolved in gold. The longer it takes, the yellower it becomes. From the outside, there are still obvious differences between the two.
2. The length of cleaning time. If gold is washed with hydrochloric acid, put the burnt gold jewelry into hydrochloric acid solution for about 5 seconds each time. But if you put aqua regia, the merchants will try their best to delay the time, because it takes time for aqua regia to steal gold. So when cleaning gold, you can look at the time spent by merchants.
So it's best not to go to a free stall to clean gold ornaments. You can go to a regular gold shop to clean it. Now many gold shops are also free to clean, and they can also clean themselves at home.