Some types of Apple® brand products are not always user-repairable or upgradable. What this means is, if something wears out, breaks, or stops working, you are unable to fix it on your own. However, you may still be able to get the device repaired or upgraded by having an authorized service center perform the work. In situations where the device is no longer repairable or has worn out, you have a few different options for the proper disposal of it.
For example, if you have a broken Mac Mini and something went wrong with the circuit board, the other parts within the computer still have some residual value. The memory, hard drive, CD or DVD drive, keyboard, and mouse are all reusable parts, when they can be salvaged. It is for this reason you will find you are able to sell the broken computer for a little bit of money.
Normally what happens when you sell a broken Mac Mini is it is tested after it arrives, and then taken apart so the various parts and components are also able to be tested to see which ones still function. Any nonworking or unsalvageable parts are then sorted out from the working ones and made available for recycling. Like in our example, where the circuit board was broken, the plastics and metals on the board can be recycled and reused to make a new circuit board, as long as it is recycled, rather than placed in common everyday garbage, where it would end up in a landfill and take decades, if not centuries, to decay.