Go to your friendly text editor on any computer, generate a blank file, save that file as .nomedia with no extentions (no file type), then transfer that file into any directory you want to block content from the media crawler in Android...
I think it works for subdirectories too, I have it blocking a few things from popping up in the albums folder...
This fix supposedly hides anything media, it almost makes it like a directory named with a . in front of it... Anything with a . in front of itself is invisible to Android crawler...
There is a supposed "risk" to using the .nomedia method, but I myself have tried to replicate them and failed, so it's been safe for me so far... The risk is sometimes it deletes the content it is trying to mask... I had a link with quite a few people expressing the same thing even up to early 2010, not sure how that plays out now, but all methods of recreating the problem were tried out and my test directory withstood the test...