Lens caps are the left socks of the filmmaking world—they're always getting lost no matter how careful you think you're being with them. And it's no wonder, because they're small and black and difficult to spot when rushing around trying to pack up. But here's a great DIY video from The Film Look that shows you how to customize your lens caps using some spray paint, velcro, and a label maker.
All of this is pretty straightforward. Choose a paint color that stands out from the rest of your gear (including your gear bag) and that you'll notice right away if you're in a hurry. Orange, yellow, maybe even some shade of red would work great. (Perhaps even white, but that's pretty risky.)
After you've taken your lens caps apart, you're going to want to add some tape to each section that is going to touch. If you skip this step, the paint will cause the cap to not function properly! Once they're all taped up, sand the caps, apply your primer, and then spray a light coat of your spray paint.Once the paint has dried, you can use a label maker to indicate which lens each cap belongs to. This makes it a lot easier to find the lenses you need, because it's labeled right on top, rather than just on the side. After that, add a bit of velcro to the cap, as well as to your gear bag (or wherever), so you can have a designated place to store loose lens caps. And there you go—customized lens caps that are a lot easier to see and harder to lose!
Source: The Film Look