Best thing for dust (not grease) is this stuff:
http://www.griotsgarage.com/catalog.jsp?L1=L1_1000&L2=L2_1001&SKU=11146
You can use it on every part of the car's exterior, even glass. (has lubricates but does not streak) Works great in the engine bay too. Is fantastic on paint, aluminum etc. Much better than just water/wet towel. I use it on my bikes too, it's great for chrome. For me it's the single most used car car product. Have the gallon jug that I keep in my gararge, the 35 oz size that I use after washing my car to touch up spots and keep the smallest size bottle (8 oz) in each car. Tried all types of towels and found these micro fiber cloths to work absolutely best w/ the above speed shine:
"11115 Three Micro Fiber Polish Removal Cloths"
http://www.griotsgarage.com/catalog.jsp?L1=L1_1000&L2=L2_1004&SKU=11115
I know it says "Micro Fiber Polish Removal Cloths" but they work unbelievable w/ the above speed shine, they're softer & thicker/ better than the other cloths they also recommend. That's the combo I use in my CF CS engine bay and entire car. Try the combo (speed shine w/ the yellow micro fiber cloth) and I guarantee you'll be hooked for life: