Dairy tomato soup poured into a meaty ninja slow cooker which had not been used for a week. Do I need to kasher the pot?
Assuming that the soup is dairy because it had actual milk or cheese ingredients. The pot has to be kashered, because now it has milchig and fleishig taste inside it. Although it was an aino ben yomo, nevertheless now it contains both milk and meat taste. It is important to add that the halachos of kashering it will depend on which materials the insert is made, and if it has any Teflon etc. coatings.
Kesiva vchasima tova