I’d like to cancel some orders that are on hold - I don’t see a way to do that.
You can either go into the hold order to start editing it, then abandon the order, this will throw it into pending, which you can then edit later and place it as a fresh order for someone else.
Or you can complete the order (make it for a test contact instead and charge it for a small amount with cash then cancel the order).
One option gives you a cancelled order, the other gives you a pending (abandoned order). Abandoned orders are nice because they stay out of the way unless you search for them. However adjusting a dropped held order that no longer is valid and turning it into a valid order for someone else keeps your records a bit more clean.
You kind of need to learn to ignore them. I normally leave them in place because they are like little clues that tell a story. When I can’t do that I just change the contact on the order to a dummy contact that I have and never see them again.