As a professor in a North American university, I receive a number of what I consider to be form letter graduate school application emails from outside the country. These emails generally feature some statement about being familiar with my research or offering generic praise for my research, followed by a description of the applicant's background and skills that have absolutely nothing to do with my research (but fall into the broader field of my department).
I tend to quickly delete these emails, but I'm concerned that not responding may be ambiguous and may further contribute to the practice of these students sending out mass form letter emails. I'm considering drafting a form letter response acknowledging that I received the email and specifying the background/skills I am currently looking for, with an invitation to send another email if the student can demonstrate how their experience aligns with my interests.
Does this seem productive? Are there better ways to respond to such emails?