In a small bowl or pint Mason jar, combine cherry pits and sugar (and husk of a juiced lime, if using; see notes). Toss until well combined, then cover tightly and set aside for 3 hours or up to 24 hours. Shake bowl or jar occasionally to toss pits around and help sugar dissolve.
When sugar has completely dissolved, strain syrup through a fine-mesh sieve. (The pits will still have enough flavor left to make a batch of cherry pit whipped cream , if you'd like to arm yourself with the perfect set of toppings for a cherry sundae.)
Season syrup with a pinch of salt and a drop or two of rose water and/or almond extract to taste. Please use care in adding these potent ingredients; while a very small amount of each can go a long way toward balancing the flavor of the syrup, the effect can be overwhelming if too much is added.
Transfer syrup to an airtight container and refrigerate for up to 1 month. Use as a dessert sauce or as a replacement for simple syrup in drinks.
