... ok people, you can't really give an answer until the OP answers the following question. The sandwich you are trying to steal from, are you only holding the 3 cards, or are you holding the entire deck, with the sandwich either on top or in the middle of a spread somewhere.
If the sandwich is in the deck somewhere, and you are say, spreading the entire deck to show the sandwich, then yes, a cull would work fine. However, if you are trying to steal from the sandwich, and it is the only thing you are holding, then things become more difficult.
If the sandwiched card is a double, and you are only trying to steal away one card, there are several methods... however, if you are trying to steal away just the one card but make people belief it is still there, you will need to master palming and various subtleties of misdirection. Either way, you will have some difficulties.