You just have to delete the plug-ins files.
You will find the files in :
For VST3 : library->audio->plug-ins->VST3->Steinberg
For AU : library->audio->plug-ins->Components
You just have to delete the plug-ins files.
You will find the files in :
For VST3 : library->audio->plug-ins->VST3->Steinberg
For AU : library->audio->plug-ins->Components