I first go over the spreadsheet and remove any duplicates and anything that looks like a bot.
How do I know something looks like a bot? When there are 12,000 different names that end with the email address .xyz or things like that linked to similar home addresses. One time it seemed like the entire city of Boise entered a lotto.
I then use a random number generator.
Today is a little tough because there are two items so two different spreadsheets. It takes me a little longer to setup at first. What also happens is that people checkout with two items so it isn't a normal single line. They appear on both spreadsheets. If I'm looking for Neenah winners and your name is on that sheet and picked, you win.