Blanch the citrus skins 3 times, in fresh water each time.
Combine the sugar, water, and glucose syrup in a saucepan and bring to a boil.
Immerse the blanched skins in the syrup and bring to a simmer. (It may be necessary to weight the skins with a dinner plate to keep them immersed in the syrup.)
Simmer over very low heat for 60 to 90 minutes, until translucent.