The soft-drink, food and drug companies have all begun to use container seals for fluids. This type of seal is almost impossible to remove unless you stab it with a knife and then remove it in sections, frequently leaving remnants of plastic-backed aluminum along the rim that will prevent the secondary seal in the twist cap from re-sealing the container after the initial opening.
The needle-nose tips of these pliers have mating jaws that will grip any seal edge firmly, and the locking ratchet-bars on the handgrips maintain the pressure until the user unlocks them. Once locked onto the seal, the pliers are used much like a key is used on a canned ham. You just rotate it across the neck of the container; the seal wraps around the jaw pliers as you do it. When you unlock the pliers, the seal slides off.
Up to this point some of you might have been muttering to yourselves that these tools are called hemostats, not pliers. Actually, they could also be called fishing pliers for hook removal, pressure clamps for fine model work, or even parcel-wrapping pliers since they excel at holding crossed ribbons in place as you tie a bow in them. As for their use in surgery, there are probably as many fly-fishing doctors who have such pliers attached to their fishing vests as use them in the O.R.