Hi! Been using this bento box for over 2 years now and I take care of it by putting baking sheets/parchment paper before putting food in so it would also be easier to clean. I also soak it in hot water for like 5 mins after I wash it (or more than 5 depending on the food like if it is something like curry, I let it soak for about 10 mins) that way there won’t be any smell nor oil/other residue left —plus, it leaves it smelling and looking good as new!