Use peels and cores from another apple recipe to make jelly. Note that this recipe is based on larger ones used for canning, but since I'm not into canning, I just made a small batch that will be used quickly.
Ingredients
Peels and cores from 5-6 medium to large granny smith apples
1 box Pectin
2 cups sugar
Method
Put 3 cups of water into a pot and add the apple cores and peels. Bring to a boil, then boil for 30 minutes, stirring occasionally.
Strain the liquid into another container, squeezing out the peels and cores in the strainer. I've read you can then let it sit overnight to let the sediment fall and get only the purely clear juices, but I didn't bother with that.
Pour the liquid into a cup measure and add enough water so you have 3.5 cups total. Put that back into the pot and bring to a boil.
Add the Pectin and mix with a whisk. Boil for two minutes.
Add the sugar and bring to a boil. Let it continue at a rolling boil for another two minutes.
If canning, put in sterilized jars while hot. If not canning, allow it to cool in the pot and then transfer to a clean storage jar or tub, then store in the refrigerator.
Recipe by Eat The Evidence at https://www.eat-the-evidence.com/2012/11/16/apple-pie-recipe-number-3141592653-plus-jelly/