A derelict building damaged in a series of deliberate fires on the Pagefield site is being demolished piece by piece.
The team of 20 people started work on Monday to pull down one of the outer buildings at the former mill and college site in Swinley.
Because it is on a listed site, they are removing it by hand so no additional weight is placed on the building and no further damage is done.
It is expected to take five weeks to complete the work.
Wigan Council has decided to remove the modern building - not the whole site - after an increasing number of fires were started there.
It has been calling on the owners of the site to take urgent action after young people were spotted there, putting themselves in huge danger.
The council served notice on the foreign-based owners of Pagefield Mill to demolish the fire-damaged building and will be seeking to recover the costs.
Coun David Molyneux, deputy council leader, said: “We took action on this as a matter of urgency and ordered the demolition of the unstable building.
“We would now urge the owners to come to the table and show us a genuine way ahead for the mill which will make best use of the site and prevent it from being a danger in years ahead.”
Fencing has now been erected around the site to protect it and prevent anybody getting inside.
Coun Molyneux urged young people to stay away from the Pagefield site, particularly during the demolition.
He said: “To young people it can feel like a big adventure park – an adult-free zone where they can explore and have fun.
“The message to young people is simple. Do not risk your lives these summer holidays – stay away from Pagefield Mill.”