Do you have CDs that have personal stuff on them and need to make them un-readable?
This will show you a quick scratch and peel method.
Step 1: Make Two Scratches on the Top of CD
Use a knife or basically anything to make two scratches on the top of the cd about half-inch apart.
Step 2: Place Strip of Tape Over the Scratches
Here I used some cheap Scotch tape. Place a strip over the scratched area, pressing it down firm.
Step 3: Peel Off Tape
Peel away the tape and with it comes a layer of the CD, making it useless. Some have suggested to use the microwave, but this can harm your microwave and cause toxic fumes. For me, this is the fastest and easiest way to ensure your data is unreadable before you trash those CDs.
For the paranoid, repeat steps and peel the entire CD.