I don’t know if this “Rub a Dub” is the same as the one published in Expert Card Technique but I do that routine combined with Flying Card from Greater Magic as a Perverse Magic routine and I published that on the Perverse Magic thread of the Genii Forum on January 1, 2011. Here’s part of it:

Flying Card – Rub a Dub

Flying Card (Greater Magic page 231) and Rub a Dub (Expert Card Technique page 301) are two classic effects that I like to do together as a routine. The ending is the only “Perverse Magic” in the routine and it comes from something I read in the Fred Braue column in the February 1948 issue of “Hugard’s Magic Monthly”.

Effect

1          The performed has each of two spectators select a card which are shuffled back in the deck.

2          The magician springs the deck and the first selected card flies out of the cards as they spring from hand to hand. 

3          The magician picks up the card from the floor and rubs it on his pants leg and it changes to the second selected card. 

4          The second selected card is rubbed against the pants leg again and it vanishes. 

5          The magician reaches into his pocket and brings out the card saying, “It doesn’t really vanish – it goes into my pocket.” 

6          The magician has a puzzled look on his face and he again reaches into his pocket and pulls out another card. He is confused. Again he reaches into his pocket and pulls out another card – and then another and then a batch of cards saying, “The problem with this trick is I – just don’t understand it..”