While I feel that modaks should be prepared on the same day, as they taste the best right off the steamer. But, if you want to you can refrigerate the ukadiche modaks in an air tight container for 2-3 days. To reheat them, place them in a steamer plate, and steam them for 3-4 minutes. Instead of making modaks in advance, I like to make the stuffing of coconut and jaggery in advance as it holds up well in the refrigerator for 4-5 days.