Ash flakes coming from exhaust

[Raykahn]

This was something I noticed today upon starting the Z. These black flakes were coming out of the exhaust, mostly driver side. They are waxy on one side and matte on the other. I don't have cats, so wouldn't be from them. I'm thinking maybe some kind of resonator packing? My car has the Corsa catback setup. Car sounds normal, no lights popping up indicating a problem.

Has anybody seen anything like this? The one in the pictures is on the extreme large size from what I saw, most are very small.