Sorry I missed this post earlier.
What kind of a “string trick”? :D
Tight ring..Doesn’t work too well with gib stones.
Take a string. tuck it under the ring..wind the rest of the string in a fairly tight coil the rest of the way down the finger. Need the coils close together.
Pinch the end so it doesn’t unwind.
Take the tucked end and start pulling forward. The ring will wind up the string and come off.