Hi Donpisci. My copy of Bobos is at my brother and laws at the moment so im not sure im thinking of the right effect. The Sympathetic Coins uses 4 coins, 2 cards and a hankerchief, and 3 of the coins pass through the handkerchief to join the 4th, yes ?
If ive got the correct effect then the one you saw would probably have been a Coin Matrix, which doesnt use a hanky. The original was invented around 1960 (so is not in Bobo) by Al Schneider and uses 4 cards and 4 coins.
jim
ps. Many of the Matrix effects are scattered throughout the literature, however the Worlds Greatest Magic series has a dvd devoted to the effect and a few versions are explained there along with Als original.