Alright so this is super simple and will take you literally less than 2 minutes to come up with a durable aluminum case for your earbuds that will fit in your pocket or almost anywhere else. Here it is: You get an aluminum tube of Bayer Cal-C-Vita Effervescent Tablets. These are usually prescribed to pregnant women to boost their immune systems and avoid the flu while pregnant. They have a lot of other great uses too but I'm not going to suggest any of them here. Ask your doctor. So anyway, the tablets come in this aluminum tube that is the perfect size for storing your earbuds. All you have to do is wash out the tube, stuff the end of a towel in there to wipe and dry it, and then you're done. See? I told you this will only take 2 minutes. Now just wind your earbuds into it, cap it, and you're good to go.
For the more creative types out there, you can customize your aluminum tube with some spray paint if you choose to; I decided to keep the original look of the medicine tube. You'll also notice that the cap fits on quite tightly and contains a freshness pack built into it. Not exactly sure if this will be waterproof once it's closed, I haven't tried to submerge it or anything but it should stand up to most weather conditions and you won't have to worry about your earbuds getting damaged if the tube gets knocked around since it's made out of some pretty durable aluminum. Well, there you have it! Enjoy!
Note:This might not work with ALL earbuds. Look at the pictures for reference.