I love this!  It cleaned up my disc drive on my 5 year old imac, which had been making a funny whirring noise for some time, and Apple told me to bring it in for repairs.  I decided to try this first, and I'm so glad I did.  I had some trouble with reading the instructions.  They are not very clear.  So I called technical support, and they were wonderful.  It did exactly what it was supposed to do very well!  I just followed step 1 and 3 and that took about 10 seconds.  It's a great product...