Thats actually a great question!
Allow me to tell you that it would be much easier to have USB drives instead. With these, it is easier to rewrite to them with more current versions of software as it becomes available. They may be a little more expensive, but at least you can re-use them many times. In the case that you would like to use CDs, I would recommend that you get the CD-RWs. They may be a little harder to find, but the price is often the same. Just like the USB drives, the CD-RWs can be written to many times.
The programs that I have on my USB drive for cleaning purposes are:Spybot - Search & DestroyAd-AwareEVEREST Home EditionFirefoxAvast
Allow me to explain these in more detail and why I use these for cleaning purposes.
Spybot S&D and Adware to get rid of all traces of 'junkware' which includes spyware, adware, and others.
Everest Home is a great tool to basically tell me what is inside the computer, without having to open it up. It is helpful in the case that they want to increase their RAM (it will tell me what kind they have, the max allowed, and how many open slots), what type of open expansion slots they have, among a wide variety of other things.
Firefox is an alternate to IE. If they are having internet problems, and IE does not work, but Firefox does, then it assists with eliminating possibilities.
Avast is a virus scanner. One of the best that I have found.
The best thing about all of the programs is that they are 100% free. Free to d/l and upgrade, with no trial periods. The links provided go to the site for d/l, but if you would like a longer list of other available software for free, take a look here
We are all curious like a cat. We wonder, we ask, we learn.
Please post back when a suggestion works, so that others may learn.