Cleaning a lens may seem like a pretty cut-and-dry operation, but when you start researching for the best information on how to do it properly, you can uncover lots of contradictory advice. It quickly becomes a game of deciding which information source you trust more, even when you’re not actually familiar with any of them.
I was reading about lens cleaning techniques recently, when I came across a very practical piece of advice: while it’s a good idea to employ various tools for lens care, such as a camel hair brush, a Giottos Rocket Air Blaster and more than one quality micro-fiber cloth, when you clean your glass, it’s equally important to keep you lens cap tidy.
The lowly lens cap usually doesn’t garner the same care and attention that’s lavished upon the lens and camera body, and therefore, it often has a much messier ride. It’s not uncommon for a lens cap to come crashing down onto a dusty floor, or take a dive directly into the dirt. The best a lens cap can hope for is to not be left behind completely.
The problem is that your lens cap often returns to the camera in a much dirtier state, and much of that mess ends up on your lens. Quickly stashing your lens cap in the pocket of your pants can be just as damning as giving it a ride on a dust bunny. Pocket lint can be brutal.
When I first became aware of this issue (which now seems so painfully obvious), I took a look at my lens caps, and sure enough, they were a mess. To add insult to injury, all of my lens caps are the mechanical sort, the kind which are pinched into place. You’d think that an easy solution for dust removal would be to dunk them in a cup of water, and to wipe them off. This is not the case. Unless your mechanical lens cap can be disassembled, submerging it in liquid can cause the internal springs to rust.
If you can disassemble your lens cap, do so. Wipe away the dust and debris, and put the thing back together again. If you can’t take apart your lens cap (most of them don’t seem to be designed to be easily taken apart), you have to make a choice. You can wash it, and try to dry it off afterward, and hope that the springs don’t rust and all is happy in the world. Or, if you want to be 100% certain everything is hunky dory, you can simply buy a new lens cap and start fresh.
You knew that was coming, didn’t you?
Canned air! :)
Why not just rinse the lens cap in rubbing alcohol or naphtha? It will evaporate rapidly and not rust any springs.