The trick is to use someone you don't likes microwave when they're not home
There were some fumes mostly from the oven bit but I had the extracter fan turned on and in advance planning also brought a freestanding fan into the kitchen to blow the fumes away from me and toward the exit.
It's not that bad I just wanted to be careful.
I used 2 CDs a plain one no backing and one with blue &white backing.
I put the first CD in for 3 seconds I put a cup of water in with it (off to the side not directly under it) it sparked and crackled fine but I wanted more crackling so I put the next one in for 5 seconds.
I messed up trying to cut them into even peices though so I ended up just cutting them any old how
Then I realised I didn't know how long to leave them in the oven for so I just put them on foil on a tray and kept the oven light on so I could peek.
They were in about 2-3 min but I got nervous they'd burn so I maybe could have left them longer?
I haven't made them into anything yet but here's a pic of my results.
Sorry for the crappy scan I don't have a digital camera anymore.
I'd definately try again with more colours and different ways of cutting them up.