BOSTON (CBS) – A cleaning solution designed to remove oil that was dumped on a South Boston memorial appears to have worked after several days of frustration.

Last week, several memorials at Castle Island and Mount Hope Cemetery were vandalized and several cleaning options failed.

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Crews applied the solution to a small part of the World War II monument last week. On Monday, they returned to wash the solution off and found it had removed the oil.

A test area of the vandalized South Boston memorial. A cleaning solution removed oil that had previously frustrated crews. (Image Credit: Ken Tucci/WBZ-TV)

The mixture that finally worked to remove the oil was a marble poultice with an asphalt and tar remover.

“They came out fantastic. It looks really, really good,” said Pat Sullivan, who was working to clean the memorial.

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Sculptor Robert Shure designed the memorial. He says the next step is to test the cleaning mixture on other parts of the monument.

“This is all about the names, the over 200 names here of guys that gave their lives so we could be here today. It’s just sad,” said Shure.

The WWII Memorial in South Boston was vandalized (WBZ-TV)

And finally, optimism is high again for clean up crews.

“I think a lot of people are going to get a lot of satisfaction out of that, so the bad guys don’t get what they want,” said Sullivan.

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No arrests have been made in the vandalism.