Ok you probably don't have to do it that often, but don't be afraid of it, give it a quick blow with your blower thingy and then get some Windex, spray it on and wipe clean with a nice soft cloth.
Mate the crap they spread about coatings and all that stuff is crap.
The stuff is tougher than mad out to be, they only do this to cover their own backside.
I clean my Canon 5D sensor with a Lens Pen and it is fine.
Be brave
Leon
