Parchment paper is used by cooks and bakers to keep food from sticking to the baking sheet without having to use an excessive amount of oil, which could change the composition of baked goods. The paper is treated with silicon so it won't burn in the oven, although it will dry out and begin to crumble over a long baking period. It can be used safely in the toaster oven and will save some clean-up time.
Size the paper to the toaster oven tray and use scissors to cut it down if necessary.
Place the paper on the tray and make sure it's not hanging over the edges or in a position where it could touch the heating element of the toaster. Though it is designed not to burn in oven heat, it will burn if directly touching a heat source.
Use the parchment paper as you would in a standard oven. Though you are dealing with a much smaller size, you can still bake cookies, small pies or frozen baked goods in the toaster oven by placing the food on the paper and starting the oven.
Remove the tray from the oven carefully, using oven mitts, and place on a heat-safe dish or rack. Cookies will easily come off the parchment, but small breads or cakes may stick to the paper and tear as you try to remove it. It's best to pull the breads off as soon as you can to keep the parchment from sticking.
Discard the used parchment and use a fresh piece for the next round of baking. Parchment paper can become brittle after use and become less effective.