[John Brown]

I sure won't pass for a fifth grader, but I got 200 hits when I type in

+air +cleaners

and then go down and tell it I want it to search for posts say, newer than 10 years old. Gotta set the year thing to where you want to search if you expect to find any thing. If you do it right, setting the <span style="font-style: italic">newer than</span> and <span style="font-style: italic">older than</span> you can narrow your search results to get posts from different years.