Yes, they do work, and some governmental agencies do use them. However, the better ones use paper-towels, and it is hard to find room for them.

First off, you should keep your standard filter which is really a full-flow oil-filter, while the "paper-towel" filter is a by-pass filter to really CLEAN the oil.

Check it here:

http://www.bypassfilter.com/

:-) neil