Any advice when using CCleaner?
CCleaner is a great tool. Personally, I love the registry cleaner - don't know if it does any good, but sure makes me feel better (I usually run it three times in a row to pick up any added remnants).
My only advice is to review what CCleaner will target and do a quick review of what it plans to delete once you've run the tool. You don't realize it, but there may be some cookies you want to save; or your web history. It won't delete anything "crucial" per se, but it stinks when you try to find something and then realize that you cleaned it off your computer the day before.
Hope this helps.