How do I clean my camera lens?

Definitely dust on the sensor. You should first try using the camera's dust removal system. Read your manual to learn how. Then if that doesn't do the trick, use a Giotto Rocket Blower to blow the dust off of the sensor. Again, read your manual to learn how to expose the sensor for cleaning/blowing.

If that doesn't do it, then using swabs and solution from Visible Dust will work.

It's probably dust on the sensor. Usually it's only visible when shooting at fairly small apertures (f16 or so).

Cleaning the sensor is not a job most people want to take on (although I do mine) - there's certain equipment/techniques that you use (& others that you defeintiely don't).

If you don't feel able to tackle it, take the camera to a professional camera store where they offer sensor cleaning services. That way, if the sensor should get damaged, it should be covered by the shop's liability.

Sensor cleaning is quite easy one you know how. But it is paramount that it is done correctly. I suggest in either taking a class in sensor cleaning or take it to a good camera shop which will cost around $30-40.

Sensor needs cleaning. You can either send it to Canon, expensive or go to a reputable camera repair company or do it yourself which would be risky. Or retouch.