Cleaning a lens is an essential skill that every photographer and videographer must have to keep their equipment in top shape and their images as good as possible. This great video will show you how to properly clean your lenses and how to, well, destroy them.
Coming to you from DPReview, this fun video will show you how to properly clean your lenses and how you should definitely never clean them. Personally, I try to work on the principle of minimizing physical contact with my equipment when cleaning it. This means starting with a rocket blower, then moving on to a more invasive method as needed. Thankfully, the glass on modern lenses is pretty durable, but still, the more you can avoid touching the glass, the better. And for the love of photography, please do not take a Dremel sander to it. If you would like more detailed instructions on how to clean all your delicate equipment, be sure to check out this article.
And given the current circumstances, it is also crucial that you keep all of your equipment clean and disinfected, so be sure to check out this article too. Check out the video above for the full rundown.
DPReview? "Don't cross the streams... It would be bad..."
This misses what I think is an essential step -- use air, like with a rocket blower to remove anything loose before you use any cloth. Get all of the potential abrasives out as well as any lint, etc. Don't forget the back element as well.
He does use a blower around the 6:30 mark when talking about sand. Good point about the back element, I've heard dust on the back element shows up more because it is closer to the sensor.
You also should use the blower in the camera -- holding the body with the lens mount pointed down. I did miss his blower comment. I always start with the blower. I frequently shoot in very dusty areas. I will carry an extra body with another lens on it to avoid having to change lenses in a particularly dirty location.