From the American Cinematographer Manual, seventh edition; The ASC Press; 1993: "1. Blow off loose dust with 'canned air'. (If 'Air' is not available, a clean, very soft, camel hair brush may be used; to remove all residual oil from the brush, first wash it in ether or pure grain alcohol and shake it out so that it is thoughly dry. Keep the brush in a airtight container. Under no circumstances should the brush ever toush skin. If it does so inadvertantly, wash it again with ether or alcohol.) Do not blow dust off with the mouth. Next to dried fingerprints, saliva is the hardest thing to remove from a lens surface without scratching it.
"2. If necessary to remove smears from the lens surface, fold a lens tissue and dampen the folded edge with lens cleaning fluid. Carefully wipe the lens surface with a circular motion, starting at the center and working toward the edges. If this will not remove the smear, take a new, clean, piece of lens tissue and and epeat the procedure using pure xylene or pure grain alcohol (not rubbing alcohol). Be careful not to touch the lens mount with the xylene or alcohol. If you do, discard the lens tissue and start over. Xylene is particularly useful in removing oil or oily fingerprints from lenses. If it leaves a slight smear after removing an oily spot, repat the action using alcohol.
"Fingerprints, or any contact with skin, may leave a residue which may permanently etch the lens surface. Never clean camera lenses with silicone-coated lens tissue or cloth." (page 144)
So there you have it, from the folks who take care of lenses even more expensive than ours. I use a blower--an ear syringe--rather than canned air. I use a lens brush after that. And I use lens microfiber cloth, which I launder periodically. If I see some dust on the lens I ignore it until I can clean it safely--never when in a hurry.