I had a non jewish friend visit me and they brought their own turkey sandwich to my house. They sat it on a plate on a cutting board for a minute while they fixed a drink. It never actually touched anything but the paper plate, but I am still worried. What should I do with the cutting board to clean it?

If there is a chance that the non kosher turkey sandwhich touched the cutting board while both the cutting board and the sandwhich were cold it is enough to wash it well with water and dishwashing liquid. If there was no chance of such an instance there is no need to worry. Rabbi Baruch Kitay