That might be the best idea, and use the new one on 120V only.
The one you have now may have (almost) melted isolation between the wires because of the heat and when you get a short you'll probably blow a fuse in your home electrical installation (or you'll have to reset the automatic circuit breaker).
How long have you used it by the way ? In general you should only keep it switched on (that is: button pressed) for like less than 60 seconds while you do the degaussing.
That's something you'll have to take into account using these Chinese tools. They probably wouldn't pass any European (or US) safety standards so NEVER use them unattended. It's the same with my UV EPROM eraser.