Mats are basically non-stop agility drills that occur before the break of dawn. Three main areas. One was outside under the stadium and consisted of running type drills (Coach Van, "get those glutes"). The second was on the old basketball court and consisted of a shuttle type drill (Mickey), jump rope and one station I can't remember. The third was the real mat drills that consisted of monkey rolls and other type of agility drills (Amato). All but a few of the drills always began and ended with being in "football position" while chopping your feet. You also had to sprint through for a few yards at the end. If you didn't do it perfect, the whole group had to go back.
In fact, I believe the morning began with everyone assembling on one room for stretching and then getting in the perfect football position while chopping your feet. Can't remember if it ended that way as well. Just doing that made your legs burn.
There were trash cans everywhere, and people used them.