A 200m (656ft) cordon remained in place on Friday with a warning issued by Staffordshire Police.
The shells were found on the site near Milestone Way, in Chasetown, on Thursday.
Members of the public were advised to stay away from the area, near a Morrisons supermarket.
The supermarket had been unaffected and remained open to customers.
PICTURES: See the police and bomb squad operation
The A5190 was closed while any live shells were detonated under controlled conditions on Thursday.
And Staffordshire Police tweeted to confirm the operation continued into the following day.
In a statement, the force thanked people living and working nearby for their co-operation during the disruption.
Staffordshire Police confirmed by 3.50pm on Friday that all the munitions had either been removed or detonated safely on site.
The cordon was lifted a short time later.
Police issued an image showing dozens of mortars which had been found.
The mortars had been gathered in containers by expert officials.
Burntwood town councillor Darren Ennis said there had been minimal disruption to people living and working close by.
"It is better safe than sorry for sure," he said.
"Businesses have been told they can continue as they are and that people may hear some small explosions.
"My business is not too far away. I've not heard any explosions at all.
"It is precautionary which I understand."
The 200m cordon in Chasetown remains this morning as colleague from Explosive Ordnance Disposal continue to make the site safe. They are expecting to make one more controlled explosion this morning. Thank you for the community's cooperation, we will update you as soon as we can. pic.twitter.com/Pm8UGDXuyj— Staffordshire Police (@StaffsPolice) May 25, 2018
Taylor Wimpey and Barratt Homes were behind the plans to build 150 more homes at Milestone Way.
The developers have already worked on building 351 houses on an area to the west of the site, although construction was delayed after previous discoveries.
The land had been once occupied by ES Smith, a company which stored war debris in the 1940s and 1950s.
The initial land had been declared safe by the Ministry of Defence following searches.
It is thought the first site built on had been a dumping ground for debris.
The second site earmarked for 150 homes had been the site of hangers and other buildings.
WATCH: The bomb disposal team work at the scene
Bomb disposal experts carried out a controlled explosion on a suspected mortar found on the site last September.
In other cases building work on a housing estate in Burntwood had to be halted in March 2016 after two unexploded bombs were discovered in less than three weeks.