I have started a brand new game and repaired my game. Other people on the official forums are having this issue. http://forums.thesims.com/en_US/discussion/comment/14525150#Comment_14525150
In this picture, ashes appeared right after the Sim drank the serum and fell asleep.
In this picture, ashes appeared after my Sim gave this Sim a serum. This is the second serum my Sim is giving this Sim.
I said I would report back if I encountered ashes and I have. A pic attached.
In this case, I can tell you that it is associated with giving a coworker an untested snake oil serum to drink. I was able to replicate it with that serum. When the affected coworker wakes up, the ashes are present. I was left with the impression that it is a by design happening. A humorous way to say "that serum flopped, clean up and start again" sort of thing. The ashes do have throw away option when hovered over.
I did also have one serum container left on the floor but I know why. My scientist was giving it to a coworker to drink when he had to leave work. Apparently, the action was interrupted by the leaving process and caused the container to be left on the floor. I went into build mold and sold it. So far, other than that one container, I haven't seen serum containers on the ground anywhere else on the lot.
I was testing my game and I was just about to post this. I don't think it is by design because the tainted snake oil serum is the only one gives ashes. The other tainted serums don't.
