My crystals get cloudy in the center every time I hold a Clear Quartz and within as little as 15 minutes. Anyone can see a visible change. I no longer use them, but keep them with my Amethyst or Selenite . I also interfere with electronics so this may some how be connected. What should I use instead of Clear Quartz if I have had this issue consistently for over 10 years?
I have a friend who also changes the look of Clear Quartz when she uses it. It takes longer for her, though and often those no-longer-clear crystals often grow into some of her strongest pieces. So, my first piece of advice is that you not assume you are ruining them by clouding them up.
Secondly, it most likely means you have an extremely strong energy that is too much for the crystal to process in such a short period of time. Perhaps you should use them without holding them. Put them a few feet away from you and direct your thoughts or your gaze to them. Since they work in part, by amplifying your own energy and intentions, and we've already determined that your energy is very strong, you probably don't even need to hold them to receive their benefits.
Keeping them among other crystals as you are already doing, is also a good thing to do.
As for what other crystals to try, I'm not really sure what to suggest. You might be having the same affect on opaque and translucent crystals and just not be able to see it. However, a crystal that doesn't absorb energy, but rather move it through the crystal structure, like Selenite, might be your best option.