How to remove sand from the lens cap?

Question

I was shooting at the beach and the lens cap fell into the sand twice. I brushed it clean, but there is still sand in the opening mechanism. I can press it to remove/place it, but I feel the strong grinding.

• Is there a way to clean this sand?
• If I use it with the sand, is there a risk to transfer sand to the lens? I think that the major problem would be sand in the rings of the lens, not on the front glass where it can be brushed away. The lens is not protected by a filter right now, because I will shoot in low light tonight. So the cap will go on the lens itself.
• Is using a slightly sandy lens cap riskier than shooting on the beach and carrying the camera around with no cap at all?

Answer

What kind of lens cap?

A lot of Canon lens caps can be taken apart very easily, which is really the most effective way to clean it.
Some Nikon caps (and all center-pinch caps) are more involved to disassemble.

Regardless, disassembly is really the way to go. Take it apart, clean all the pieces individually, and reassemble.

If you do not feel up to disassembling it to clean it, I would just buy a different cap. I would not use water, as most center-pinch caps have springs in them, which will rust.

The thing I would be most worried about is getting sand in your camera-bag, as it could then migrate to other parts of your camera, get in the mirror-box, etc...

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Here is the construction of a Sigma Center-pinch Lens Cap.

As you can see, it has two steel springs, which would likely rust if you get it wet.
Disassembly is quite simple. The clips on the two removed tabs are what hold them in. I simply nudged the clips with a screw driver, and they popped out.

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