The junk filter is a learning filter. As you add more files of the same nature/characteristics, (eg: files of 765 KB in size) then the filter gradually learns to filter those out. Certainly the common harmless spam like the autogenerated spam results, & also autogenerated mp3 spam results are very easy to filter out. It only took me 2 searches to totally eradicate those from search results by searching for terms that would deliberately promote those type of results. However virii files are much more difficult to filter out. It takes much much longer. Other virii sizes to filter out are 399 KB, 851 KB, 60.5 KB. You may want to check your filtered results however to make sure you don't filter out the wrong items by mistake. I guess it also depends upon the intensity of the filter you set it to under Tools>Options>Filters>Junk