Question

'The old-style currency was of no use to Charles'. Explain.​

Answer 1

Charley had tried to buy the tickets from clerk and the clerk thought Charley was cheating him as he had modern currency notes. The modern currency was perceived as fake notes by the clerk. To escape the arrest, he fled back from the scene.
Next day, he went to a coin collector and bought old currency notes worth two hundred dollars in exchange of three hundred dollars in new currency notes.
But he still couldn't buy the tickets, even after getting the 1894's currency, as he could never find again the corridor that led to third level.