Maybe a common technique, but I've not read about it so I'll share. Works for me much better than the swinging hammer technique.
In the final stages of milking a stubborn splice, I use a friction knot to 1) give me a MUCH easier place to pull with my hand and 2) even better I can easily wrap the end of the hitch rope around a hammer handle or something like that and pull hard very easily. You can hear/feel the splice close using this technique even when the hammer method has run out of steam.
The exact hitch isn't important, and I find a pretty big cord is better because it doesn't bite the splice ropes as much. In this pic I am using HRC prussic cord on 11mm bandit (lanyard). The knot is like a blakes with only three wraps, four grabs too much for this application. I am sure other hitches would work well, but this has worked so well I stick with it.
To begin with I milk ahead of the hitch with my hand, and then only actually use the hitch where the splice rope gets fat. The beauty is that because it's a friction hitch, I can yank on the hitch with my handle on the hitch rope, and then still holding tension, slide the hitch out a little by easing up on the knot (arborists style). They with straight arms and a pull handle I can yank a few times (still feeling/hearing if things are moving) and then ease the hitch a little more toward the splice end (still under tension to hold any slack I've pulled) and repeat.
For me it's really a miracle. It's simply astounding how well and easily a the yanks close the stubborn splice that isn't impressed with the hammer in the eye shock method, and using a handle makes it so very easy on the hands.
Milking the splice with the hitch makes it easy to close small eyes.
