Jordan Parry, 16, Darren Melrose, 18, and a 17 year-old girl fled with the items and left bottles strewn at the entrance behind them.
The trio were spotted by a man who was paying his respects to a friend who was killed in the tragedy, on November 29, last year.
Police were alerted and the teenagers were seen on CCTV cameras forcing their way into the empty pub.
Officers then heard them smashing charity tins off of the pavement and saw piles of coins and bottles of alcohol.
The three pleaded guilty yesterday at Glasgow Sheriff Court to breaking into the Clutha Vaults pub, while acting with another, and stealing charity tins, cash and alcohol.
The court heard £171 was the amount taken from three charity tins and a quantity of alcohol too.
Sheriff Joseph Platt deferred sentence on each accused until next month for reports and remanded them in custody.