She's speculating on what the mechanism could be as often when these are cleaned off they're white instead of red and therefore not actual clots of blood. It's a viable mechanism aside from shouting "nanomachines, son!"

She's speculating on what the mechanism could be as often when these are cleaned off they're often white instead of red and therefore not actual clots of blood. It's a viable mechanism aside from shouting "nanomachines, son!"