I used an old Mac SE for this project. To crack the case, there are just a few screws to pull. They are torx screws, If you do not have a torx screwdriver, a flathead will work. Once the screws are removed, the front pulls off easily. Just get your fingernails along the crack and pull.
Really, it is not that hard to do.Here are some other instructions on how to crack open a Mac
Once you have the case open, remove all the electronics and discard. You will have to look for screws. Be careful of the monitor, sometimes high voltages can zap you! Wear a long sleeve shirt in case the monitor breaks. Don't worry too much, just be careful.