This has been discussed several times here. For the body of the lens, get some aluminum polish and paste wax from your auto parts store, some old rags and have at it.
The glass (front/back) is best cleaned infrequently w/ 1.) a squeeze lens blower (available at most camera shops) to blow off the dust, 2.) lab grade (pure, no fingernail polish remover) acetone on a Q-tip in small circles, 3.) then a mixture of a bottle of distilled water/ drop or two of of liquid dishwashing detergent. After applications of acetone/ water w/ one end of the Q-tip, dry w/ the other end. Many others have other methods/ formulations, but this has worked for me.
Unless you touch the lens or spill some liquid on it, just blow it off w/ lens blower from then on after using.
