What are the easy ways to skim off the scum and fat from soup & stocks?
@moscafj is correct
Another, more wasteful way, for a small amount of fat on the surface is to drop a paper towel flat on the surface just long enough for it to get wet, then pick it up from the center and discard. This picks up fat and scum bubbles, but wastes a paper towel and some of the soup or stock. It doesn't do great for things on the outside edge, but another paper towel can get those by swiping around the edge. I usually do this only after skimming.
(Someday, I'll get around to using a vacuum with a homemade aspirator bottle to see if I can vacuum off the fat, but it'll have to be something that's really easy to dump out and put in a dishwasher.)