Otoshibuta is a small lid that is smaller than a pot.
There are two main reasons why we use otoshibuta:

  1. To prevent ingredients from breaking up.
  2. To let the flavour of the broth soak into ingredients.

Substitute for otoshibuta

Fold an aluminium foil to fit the size of the pot and make a few small holes. An aluminium otoshibuta might melt if used for a long time. However, as long as used for regular cooking, there is no adverse effect on the human body.