The strong adhesive used on the label is, to put it bluntly, an organic resin. Organic matter is incompatible with water, so it cannot be washed off with water. It is also difficult to remove with a wire brush. Use wine. Vinegar, dishwashing liquid, washing powder, soap, and boiling water cannot wash it off. Since it is an organic resin, it must be washed with an organic solvent. It is very easy to wash off using strong solvents such as ethyl ester and butyl ester, but most people don’t have these.

In fact, there is another commonly used organic substance around, which is dish soap. Didn’t I just say that dish soap can’t be used to wash it off? I may have tried it all, but the glue couldn't be removed with dish soap. But if you don't use water, just pour dish soap directly on the glue, and then brush it with a wire brush. It will be brushed off easily, clean and smooth.

It turns out that dish soap is generally a high-grade alkyl sulfonate + a trace amount of surfactant. The high-grade alkyl part is organic and is compatible with adhesives, while the sulfonate part is inorganic. , so it is soluble in water; when you dilute it with water, the alkyl content is very low and is incompatible with the adhesive, so the glue cannot be washed away; when water is not added, the alkyl content is sufficient and it is compatible with the adhesive. , so the glue can be easily washed off.