Two sculptures by Jacob Epstein, valued at £43,000, were found by the police wrapped in a bin bag in the back of a mobility vehicle.
The bronzes, "Adam and Eve" and "Burial of Abel" were removed from a cabinet at Watford Museum by thieves who had no idea of their value.
The man who was storing the works of art was being paid just £100, but panicked when he realised their worth, St Albans crown court heard today.
Adam and Eve, which dates from 1938, was valued at £25,000. The Burial of Abel, from the same year, was worth £18,000.
They were taken from the cabinets at the museum in Lower High Street at around 3.30pm in Saturday, July 13.
Allen Buckley, 45, of Caractacus Cottage View, Watford was convicted of theft and jailed for 30 months.
Graeme Rowe, 58, of Aashiana Court, Jellicoe Road, Watford, pleaded guilty to handling stolen goods and received a 20 month jail sentence suspended for two years.
Another man is due to be sentenced at a later date.
Police raided Rowe's home on July 30 and found the sculptures in the boot of his car, wrapped in a bin bag. He was not prepared to say who had asked him to look after them.
Richard Storey said Buckley had been involved in an opportunist walk-in theft.
"He had no idea of their significance and importance. Mr Buckley is an entrenched drug user and that day was 'bang on it' to use his term. He has a long term habit using heroin and crack," he said.
For Rowe, David Smithet said: "He was approached by someone to look after two items and hold them for £100.
"When he Googled them and realised their value, he rang the person who approached him and said he no longer wanted to look after them.
"Before they could be taken from him the police arrived."
He said wheelchair-bound Rowe was awaiting surgery on his leg and has been told the operation has only a 30 per cent success rate.
Judge John Plumstead described Buckley as a "scavenger" with an appalling record of petty crime.
He said: "The objects you stole were for public enjoyment in a museum. It was a very serious theft indeed."
He passed the suspended sentence on Rowe because of his health problems.