Prison break: could you escape from jail using a wet shirt?

In the film Shanghai noon, Chon Wang (Jackie Chan), a Chineseman in the US and his new-found friend, Roy O'Bannon (Owen Wilson) a small-time robber, are trying to escape from an old-style Wild West jail which has metal bars from ceiling to floor. Wang does a very odd thing. He takes off his shirt, tears it up into strips and urinates on them. Holding them up he proclaims: 'when the shirt gets wet it doesn't break'. Then knotting some of the cloth around a pair of prison bars and using a broken -off wooden chair leg as a lever, he tightens the knot which bends the bars so he and his mate can get through and escape! So is this possible? Is wet cloth really stronger than dry cloth?