No matter what kind of 3.5 mono plug is used for a long time, it will oxidize the surface, which will lead to poor contact. Therefore, it should be protected if it is not used for a long time. At present, many audio input and output devices will have plug sleeves at the time of purchase, which is the best protection. If the plug has been oxidized, you can use the following methods (the above method is the best, the following method is the worst)
1. Use dilute hydrochloric acid, very dilute is enough, use a paper cup to hold a glass of water, dip the concentrated hydrochloric acid with a glass rod, and throw it into the water (be careful when operating, do not throw it all over the world, and must stay away from concentrated hydrochloric acid Bottle mouth), shake it a few more times, and then soak the entire plug in. It will be fine to stir and stir for a long time, because silver and copper will not react with hydrochloric acid, then take it out and dry it.
2. Wipe gently with toothpaste, wipe gently, and rub for a while. If it is hard, it may scratch the plating layer, and if it is scratched, it will also make poor contact.
3. Wipe with cardboard, don't follow the lines, but also wipe lightly
4. Use rubber, this should be hard, but it is not easy to wipe, and some places may not be wiped
5. Sandpaper, fine sandpaper is better, coarse sandpaper is about to die, 3.5 mono plug is best not to use this method.
