If you want to filter away certain results permanently (based on e.g. file size or name), create a free filter called "Ignore", and put two jumps in it; one to "DON'T DISPLAY" and one to "DON'T DOWNLOAD". Now you can jump to "Ignore" instead of "DON'T DISPLAY". This way the filter execution will abort immediately, instead of trying to run the rest of the calling filter.
To see which files have been tagged for download, add a rule to your Global (post) filter; If state flag "DOWNLOAD" is set, jump to "DON'T DISPLAY" with "Mark only". Now your auto-downloaded files will show up in a different colour in the search results.
Apparently some pieces of software like to respond to every search they come across, and feed back bogus results. You may have come across files with names like "!!_YEEHAA_!!_(search term).exe" or "secret paysite passwords for (search term).html" and similar. Zygo has a nice trick to weed them out: Specify your search with the words jumbled, like "clones of the attack", and use a filter to remove results that has the same order of the words; "If file matches the regexp "clones.*of.*the.*attack", DON'T DISPLAY".