We have a baby’s high chair (with a plastic tray that the food is put on) that is used the whole year for chametz (even sometimes hot). What can be done in order to use it on Pesach? The baby that will sit there is quite active and will perhaps rip off whatever tin foil that might be put. As well putting the thicker tin foil if he is able to rip it off is somewhat dangerous since usually it has sharp ends.
Boiling water should be poured over the tray a day after the tray is cleaned from chametz, and for a baby this is certainly sufficient.