Go to the SoundCloud website
You must be signed in to your SoundCloud acccount. Start playing any radio or song and hit F12 in your Chrome browser and go to the ‘Network’ tab in your browser developer console. There you will find values like: https://api-v2.soundcloud.com/dashbox/listen?&client_id=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Simply copy the client_id parameter and you are done, you have a new SoundCloud API client ID.