Where are you trying to track it? You could post to the log file the part number that was being run each time the program was started. If you use textmsg() you can send information to the log file. There are two strings available to you in the method so you can also concatenate a string with the variable.
Say before start I have the operator enter a part number
Part Number - 123
What is the best way to track it? For example a week later there was a problem and we wanted to go back in check it and make sure all the numbers added up.