managing icons

[Dan10D]

When and how exactly are the unreferenced icons removed?

I have numerous icons I do not want - and by far most are unreferenced - and none are being removed. I have some I want to keep that I have not used.

Or is the question only about how to delete USED icons? Is there a separate (easy) way to delete unused/unreferenced icons?

Have there been any more development in this area?