The volcano, which had been dormant for four decades, erupted on Wednesday, sending a plume of smoke and ash 10km (6 miles) into the sky.
Authorities evacuated people living within a 21km (13 mile) radius.
Road workers used lorries to plough through the ash, which lay up to a metre (3ft) deep in some places.
As the massive ash cloud drifted south, emergency workers handed out protective masks in a wide area including parts of Chile and Argentina.
"The ash might damage crops, animal feed, bridges, roads, people's work routines, tourism and especially their health," Michelle Bachelet, President of Chile's National Geology and Mines Service, said.
The first eruption on Wednesday evening lasted about 90 minutes and send a huge mushroom cloud of ash into the sky.
Seven hours later the volcano erupted again, this time shooting lava into the air and generating volcanic lightning.
There have been no reports of deaths or injuries.

The figure, based on the American toy GI Joe, was first hit shelves in 1966 and quickly became a must-have.
Palitoy, based in Coalville, Leicestershire made its own British version with beards, gripping hands and "lifelike hair".
Fans and collectors met on the "sacred ground" of the former factory, now a conference centre, for AMCom16.
The action figure - never called a doll for fear of alienating boys - was hugely popular in the 1960s and 70s but then lost out to Star Wars.
Meanwhile, Palitoy shifted manufacturing of all its products abroad and by the mid 1980s had ceased trading.
Bob Brechin was the firm's chief designer and modelled Action Man's famous grip on his own hand.
He said: "[Collectors] don't grow up do they?... They are reliving their childhood really. It's great that they do because it keeps it alive."
Organiser Alan Dawson said it was a nostalgic event and many people had brought their children to show what their own childhood was like.
"The genius was calling it Action Man because it opened up the door for non military - the football player, the Olympic athlete, the rock climber, the Arctic explorer. Parents who didn't approve of war toys would still let their children play with them.
"It's become part of the DNA of that generation, those generations between 1966 and 1984."
Residents and emergency workers in southern Chile have been clearing ash that rained down on towns after an eruption of the Calbuco volcano.
[NEXT_CONCEPT]
Fans of Action Man have gathered at the spiritual home of the popular toy to celebrate his 50th birthday.