I've been hoping someone would offer a brilliant solution as I have the same question. I stand on a chair and clean with a Norwex environmental cloth. That's the easiest technique I've been able to come up with.
Once a month, I drape plastic below my fan, taping the corners to the ceiling leaving working space. I dust off as much accumulated dirt/dust as I can. Then I use a household cleaner sprayed on paper towels and wipe the blades clean. Slowly remove the plastic one corner at a time, bunching it as I go along.
I've found if I just never turn it off I don't notice the buildup.
One of of the easiest ways to clean the fan blades is to use an old pillow case. Slip it over the blades and pull it across the blades it wipes them clean. In between that time I use a Swiffter to do a fast dusting.
My suggestion is a pillow case as well, preferably a king sized one. If there is more than just surface dust, after that is removed you could spray down the blades with a mild cleaner and wipe with a pillowcase again or wet down the pillowcase on the second pass.
I used car wax (buffed) on the blades when we hung our ceiling fans. It helps keep the blades smooth so not as much dust collects. Then every other week I use a folded (gets both sides of blades at once) micro fiber cloth to wipe the blades.
It should be attracting more dust being greasy
not if you put on a thin coat of paste car wax, let it dry then buff it
I like to dust it off with a vacuum cleaner first then I use a little dawn soap in some hot water and wipe down the blades.