I just bought a CD Scratch Repair Kit. I had a few CDs that used to skip a lot, usually about 75% of the way through (never toward the beginning of the CD; don’t know why). I followed the instructions as well as I could.
It’s got two bottles, some cleaning cloths, and a little CD holder. It told me to put a few drops of the first solution on the CD, which has hard to do since it was a paste even after shaking vigorously. Then buff it off with a cloth, and use the spray, and polish that off with a different cloth.
Looking at the CDs aftewards, the scratches were definitely harder to see. I did four CDs without testing any of them, which was probably unwise because…
Now my CD player won’t read three of them! It just spins and spins even after you hit stop. It only stops when you hit eject, and even then the CD is still spinning when it opens.