Is there a tool that can cut flat 5mm-wide aluminum jewelry wire to leave a rounded end? (An as-yet nonexistent extremely heavy duty nail clipper comes to mind).
In the image below, the wire on the left is an example of what we started with. We've used a grinder to round the end of the wire on the right. If we could just cut it in a round shape and then polish the end, it would save a lot of metal dust about a minute of grinding per end (and we may have hundreds to do).
An answer to this other question mentioned the use of a deburring tool, which may be useful after making a round cut.
This metal piece helps snug a medical mask to a person's nose. We wanted it to be rounded to prevent it from breaking through the material. My wife is making medical masks for friends that are health care providers who are worried about the current mask shortage. Hers is a five layered design that I'll encourage her to post soon. Without this metal piece, air leaks around the nose.
UPDATE: "Normal" toenail clippers actually worked well enough. I hadn't thought about actually trying them, but after the accepted answer below suggested something we thought flimsier than toenail clippers, we went ahead and gave toenail clippers a try.