How to determine garbage string value in ios?

Question

I ran into one problem related to some garbage cost,

In the database, it looks like the following: (SQLiteManager)

After setting the debug mode, it looks like this:

And when I print this object, it will print some unreadable line.

So how can I determine this value? I need to identify him, please help me.

EDIT This looks like the hexadecimal characters in it, can someone tell me how I can detect or remove from the string?