So I have all these templates

I’ve created several custom page templates for my theme — “Template” has more than one meaning, so to make it clear, I’m talking about this: http://codex.wordpress.org/Page_Templates — Anyway, I’ve created several, some of which I’m no longer using. Is there any way to quickly check which pages use which templates? I know that I can “edit” each page individually, but I have a lot of pages, and that will take a long time.

What I’d like to do is quickly establish which templates are being used by which pages. If there’s any templates not being used, I’d like to get rid of them. Also, there’s some old templates which should not be used any more. If there’s any pages still using them, I’d like to know so I can change them to a newer template.

Any ideas?