Rats have considerably larger droppings and WAY more urine than mice. So if the droppings are quite small, it was probably mice.
I would clean everything very well and set some good old fashioned traps to get any that may still be in there. I made the mistake of leaving poison bait out in one of my trailers years ago and a rat ended up dying somewhere in a furnace duct. The smell was absolutely horrible and we never could get rid of it. From that point on, I concentrate on keeping rodents out and trapping any that may get in.
Good luck and let us know how you make out.