Now it is time to clean the lens cover. First use a brush of some sort to brush away any visible debris. I use a lens pen, but any soft, clean brush will do. If you have some canned air etc, you can use that to clean up the cover.

Personally i used a straw to blow away debris from the hidden parts of the cover. If you choose to do so, be aware that the humidity from your breath will condense on the cover.

to properly clean the curtains, you need to access them. By squeezing the plastic tip towards the clip marked with arrows the curtains should close. By repeatedly squeezing and letting go while blowing, the rest of the debris should come loose and the curtains should move freely.

Be careful! If you squeeze hard, the inner plastic ring will detach from the outer frame, giving you a lot of extra trouble.

DO NOT use any lubricant. This will work perfectly well for a day or two, but the first time you put the camera in a pocket etc, the lubricant will attract dust lika a magnet, making the curtains get stuck again very quickly.