a) a fairly sturdy ring that isn't too soft
b) a closed bottle of some sort
(for purposes of this demonstration ignore the fact that IBC root beer comes with twist off caps, this trick will work for all standard bottle caps, most usefully being those which require the use of a bottle opener ;-)
Step 1: Know Your Enemy.
So where to find something hard to pry that little sucker off?
Step 2: One Ring to Rule Them All or at Least Get Them All Drunk...
1) a hefty but not overly large lower part that can be grabbed by the bottle cap's "teeth"
2) a broad face that won't dig into your finger when you put pressure on it.
In this case I'm using my stainless steel rat ;-) so it's pretty impervious to damage under normal circumstances (24k gold might not hold up so well for this sort of thing)