Only tangentially related to MojoPoly, but the "._" 4k files were driving me a little nuts.
Blue Harvest, developed by Ross Tulloch (ZeroOneTwenty), is a discovery I made today. Wasn't a fan of the price at $15, but I guess this is a pretty niche product, and niche products tend to be pricey. Seems to work pretty well. Doesn't stop OS X from making the files, but goes in afterwards and deletes the created files.
Still testing, definitely works on newly created OS X invisible and unnecessary files, but not sure if it works on older invisible files that were already there. Seems to, but need to test on all my micro-SD cards.