When I applied, the vast majority of my volunteering was non-clinical. I had many hours over a few years as an event organizer and snowboard instructor for a program that brought disabled and/or underprivileged kids to the mountain to learn to ski/snowboard. Several interviewers asked me about it, and since I was actually passionate about the program and enjoyed working there, I could speak about it enthusiastically and at length. I can't say that teaching kids to snowboard got me accepted, but I think it helped.
Now I occasionally interview applicants at my program and it is obvious when they volunteered to do something they enjoyed vs something they did just to check off a box on their application. Obviously, you need some clinical exposure to convey your interest in medicine to the application committee. But if you are involved as a volunteer with something that you are passionate about I think it will be a valuable addition to your application.