Psychic credit card

Psychic credit cards, like the Doctor's psychic paper tricked machinery or those who looked at it to believeing it was something else. The Doctor gave one to Captain Jack to help him look after Das, the neanderthal sent back in time to Bromley in 2005. It's possible the technology to make psychic credit cards originated from the 51st century, as Jack was familiar with them, commenting that they were banned after the infinite recession on Baydafarn. (DW: Only Human)