Deebie said:Oh God, what does spider or millipede poop look like? Or do I really want to know? 
I never thought about that. 
We have spiders around our front door due to all the lighting. I used to have a wreath on the door, but started noticing black specks on the flowers that didn't rub off. It was spider poop coming from the spiders that were "nesting" above the door. The ones next to the doorbell, they'd leave black specks of poop on the siding.
My big 'Aloe Vera' had black specks on some of its leaves that rubbed off when I wiped them down. More spider poop lol.
First picture: You can see what looks like potting mix packed around a couple of the holes. I believe some of that is millipede poop and some is potting mix.
The second picture is a mix of millipede poop and potting mix. It's kind of hard to describe what it looks like, but it's little brownish black balls (sometimes it's just brown).They keep pushing potting mix and poop out of the bottom holes of this plant's pot. I'll clean them off and a day later, there's more stuff in the plastic container. I bought a 'Pothos' earlier this year that had them and I'd find the occasional dead millipede.
They eat decaying matter, so I don't mind their prescence.
