Apricot jam can be made with the skins. It is a texture difference you'll notice. When someone says "old-fashioned" apricot jam... I'm picturing with the skins. Because older recipes were simple and straightforward. If you've got a tree full of apricots you need to get taken care of, you'll leave the skins. If you want smooth and silky, peel the apricots just like peaches. and make jam out of the pulp only. When you are boiling your jam you can see the skins floating around. You can pull them out with a fork and leave them out. Or you can chop them up, and add them back to your pot. This way you'll get some skin texture without the big chunks. (My guys don't like the big chunks.)