Combine citrus peels and an equal amounts of sugar by weight in a bowl.
Let sit at room temperature for 2-3 hours - or even better for a day, shaking occasionally, until the sugar has dissolved and a syrup has formed.
Strain the syrup through a fine-mesh sieve, pressing on the peels to extract as much liquid as possible.
Store the syrup in an airtight container in the refrigerator for up to 2 weeks.
