You can delete objects from the content libraries that you have delete rights to.
Do the following:
Open the QMC: https://<QPS server name>/qmc
Select Content libraries on the QMC start page or from the Start drop-down menu to display the overview.
Select the content library that you want to delete objects from and click Edit.
The content library edit page opens.
Select Contents under Associated items.
The contents overview is displayed.
Select the files that you want to delete.
Click Delete in the action bar.
A Delete dialog is displayed.
The files are deleted from the repository and removed from the contents overview.