Thanks for getting back so quickly. The particles that were caught in the screens were easily broken up and dissolved when I rubbed them together between my fingers. I did find a couple of plastic-like pieces, like teflon tape or other debris, but 98% was the easily dissolvable calcium.
Before putting the aeroator screens back on my faucets, I took a fine vegetable strainer and flushed the pipes through the strainer to see what would collect. For the first few minutes I would catch more of the particles. I found by turning the water off and on quickly, more particles would accumulate. After 5 minutes of this (on both hot & cold), the strainer would not collect any more.
I’m continuing to monitor the faucets and flush as necessary. I have a feeling it will run its course.