Just be sure to "unlock" the blades before turning the fan back on.I don't have any problems-just hold the fan prop with one hand a use a vacuum tool or rag with the other.
I have a tool for my Kirby that has guides on both sides. These guides hold the blade as the tool slides over the blade. Holding the blade in place as you clean it. It's the best thing I have found for cleaning the ceiling fan so far.