The RFID chips that you found on clothes, books and electronic devices... they are to detect you at the doorway, not inside the store. Example:
These type of RFID chips are the most commonly used in bookstores, drug marts, electronic markets and clothe stores. They are widely produced, and completely useless against shoplifters. There are 3 methods you can deal with them:
Rip it off, of course. This is the most simple but it damage your product's package, example a book or a can of baby formula.
Hammer it. RFID chip can be destroyed by direct impact. Hammer is preferably the best tool to quick disposing the chip.
Tin foil, my conspirators. Wrap your products tightly with tin foils leaving no open. Or if you could construct or get your hands on a Faraday bag, this works too.