i always advocate practicing with water. I spilled too much real stuff while I was pouring back from the sample cup to practice again.

The thermometers won't contaminate the quick fix.

Practice and you'll know (about the heating pads and how hot it gets).

Practice and do your pretend sample giving in a closed bathroom. Practice being quiet and efficient. See what the temp is every half hour and guestimate how long its going to take you to give your sample at the lab or facility.