A microwave oven is just a magnetron (which generates the radio waves) a waveguide (a tube the radio waves travel down) and a box for the radio waves to end up in. It’s generally expected that there will be something in the box to absorb the radio waves and get hot. If there’s nothing in the box then the radio waves will bounce all around in there, possibly eventually finding a path to bounce back into the magnetron which can possibly harm it. The same goes for putting anything that might be reflective to radio waves inside the box. It can cause excessive amounts of radio waves to go back into the magnetron and damage it.
That said, I don’t think it’s very likely that you could damage the magnetron from a CD, but I won’t guarantee that you won’t. The risk is low enough that I’ve nuked a couple of CDs. I should also add that I used the microwave at work, not my own.
FYI - Steel wool also makes a rather pretty display.
I wonder if two rounds in the hole-punch at work wouldn’t make it more or less unusable too? If you have a strong one. Perhaps a quick run over it with an engraving pen or soldering iron would also do the job if your company doesn’t want to invest.
Putting them face down on the parking lot and driving over them in your car would probably leave them unusable too
I knew that cutting them in half would work but I am always afraid I am going to lose a finger doing it that way.
I am going to try the sand paper/black sharpie and the hole-punch ideas first.
I tried to get the boss to buy a woodchipper but he said no.
Hauky, you must have some strong hands if you can fold them in half with one hand. I have to use two hands to cut them with scissors. Maybe I need to get a better pair. (of scissors, not hands.
Personally, I snap them in half inside a trash can. But you may want to try using a paper cutter, it’s safer and faster than using scissors.
A strong magnet will work for magnetic media (floppies, Zip disks, Jaz disks, hard drives), but not for CDs, which are purely optical media. Even CD-RW media is recorded without the use of magnets: heat a spot to a low temperature and it becomes reflective, heat it to a higher temperature and it stops reflecting.
I’ll second the earlier advice of scratching off the media layer. Use something like steel wool and completely remove the label/media surface. This will make the CD unreadable by even military-level technology. If you just want to make sure that no one can read it without serious amounts of work, snapping it in half is a simple method that cannot be easily corrected.
After generously gouging both sides, get a drill and drill a dozen or so holes, the bigger the better. If you have a bunch, put em on a spindle and do them in bulk.
As K2Dave suggests, the plastic layer between the label side and the metal layer is very thin indeed (this is why you aren’t supposed to write on the label with ballpoint pens) scratching the label side with something pointy will destroy the disc; scratching the underside (the ‘read’ side) may not destroy it unless you scratch deeply enough to get through to the metal layer (and you’d have to press really hard to do that); if you just scratch the plastic, it’s possible that a determined person could polish out the scratches, coat with a layer of laquer and be able to read the disc.
Wood chippers are also excelent at bulk paper shredding, if you think that you might be able to sell him on a dual use item. The CIA Headquarters has a facility with several wood chippers set up for disposal of classified paperwork.
Get an ordinary ballpoint pen and scribble on the label side of the disc; you only have to press moderately hard. Turn the disc over and look at the readable side - you will be able to see the damage, just make sure that you scribble over the full width of the tracks - you don’t need to cover the whole surface as long as you span the width of the tracks.