Your thoska is handed out together in a protective cover, which should protect the sensitive thermo-rewrite strip. If the protective cover breaks, you can get a new one in Department 1: Studies and Teaching. It is strongly recommended to keep the card in the protective cover to protect it from damage. You should only remove the card from the protective cover for payment purposes or loading money onto the card only.
In order not to damage your thoska, you should absolutely avoid the following:
Bending the card
Chemical influences (e.g. washing / contact with other liquids)