CD,DVD,CDR,DVD-R,DVD-RAM MEDIA what to actually do with them

Hi everyone,

I have been collecting CD and DVD media as in the discs themselves not the readers/drives. I have been looking for a clear answer to the question "what metals do they contain?" for a long time. Searching on this forum is a nightmare because hits talk mostly about the drives. I came across a post a few months ago with semi useful info but can't find it anymore.
So what i (so fa)r think I know about it is that most music CDs and pressed CD-ROMs that look silvery are most probably aluminum and thus worthless in the sense of extracting metals. CDR, DVD-/+R and RW can be silver or silver alloy and even gold if you have old ones that look gold. There's a video on youtube of a guy extracting the metal from a bunch of CDs and ending up with a blob of something that he jokingly calls silver.
So .... is there anyone here that was actually involved in the production of CD media or has experience extracting metals from CDs? And IS there a way of visually sorting them? I mean the silver and aluminum ones?