I had a slip recently and I decided to turn my K9 into a white-list filter! I admit it's a crutch, but I need crutches at this point.
How did I make K9 into a white-list filter? I added COM and NET and ORG into the blocked keyword list. If there's any site I need to use (and there are truly very few sites I really need to use), I can add it to the list of website exceptions to allow.
At first I was a bit depressed about trying to find p*rn on my computer a few days before Rosh Hashanah. But then I thought, what really counts is what I do afterwards. My general approach NOW is to be on the lookout for pitfalls, and do my best to remove them, and as soon as possible. That's a pretty good plan to show up in front of Hashem with.