Open the mobile phone QQ in the mobile phone, and the method of iOS/ Android mobile phone is universal. After opening QQ, switch to the message interface, and then click "Personal Information" in the upper left corner. Click "Settings" in the lower left corner of the pop-up menu, as shown in the figure below.

In the QQ setting interface of mobile phone, click the "chat history" option to find the "clear cached data" option, as shown in the figure below.

Click "Clear Cache Data" and a confirmation operation of "Clear Cache Data" will pop up at the bottom of the screen. Click to clear the QQ cache of the mobile phone. Wait a moment, and you will see the prompt of "successful cleaning" displayed on the right side of the figure below, as shown in the figure below.

At this point, we have successfully cleaned up the QQ cache of the mobile phone. I suggest you clean it regularly every once in a while.