Water cups with glue are harmful to your health. Because glue generally contains a lot of chemical solvents. Although these solvents are slightly toxic, they are carcinogenic. For the sake of health, it is best not to use them.

If that cup is important or must be repaired, you can use an electric soldering iron. This is a very useful skill. The specific method is:

Go to the supermarket or grocery store and buy a 30-watt electric soldering iron, which costs about five yuan.

Plug it into the socket and wait for three to four minutes.

Put the welding head flat on the crack, gently press it, and brand the crack back and forth. Be careful not to burn it lightly, usually just for the sake of beauty. Brand covers are basically new, non-toxic and tasteless.