There is no need to clean up the memory without jailbreaking the iPhone. Just restart your phone often.

You can use Tencent mobile phone housekeeper to clean up after jailbreak.

Enter the main interface, click Memory Cleanup, and then click the phone in the upper right corner to slim down.

Select Wechat Cleanup to scan junk files, software cache and chat file junk in Wechat.

Click Clean after scanning to thoroughly clean up the cache space of WeChat.