Mashed potatoes
These are really a no-no for your pipes. Mashed potatoes, or any type of potatoes, might seem harmless enough to be thrown down in the garbage disposal, but it can seriously affect your pipes.
And while we’re on this subject, you should know another thing: any kind of starchy, fibrous foods(meaning potatoes, celery, corn, corn husks, skins, asparagus, and artichokes) expand if you throw them in your garbage disposal, wrap around its impellers, damage your motor and cause a big backup.
If you want to avoid that from happening, try to clean as much as you can from the container with a paper towel and throw it in the trash.
