Two International Space Station Russian cosmonauts went on a six-hour spacewalk to install new equipment and perform maintenance tasks - including the cleaning out of windows.

Station commander Gennady Padalka and flight engineer Mikhail Kornienko started the ISS housecleaning on Monday, floating 250 miles (400 km) above the Earth's surface, and ended 30 minutes ahead of schedule Wednesday, at 3:51 p.m. EDT.

The equipment they installed was to help crew members maneuver outside the ISS. After installing, they checked up on various experiments and then finally cleaned a porthole window that had years of dirt from exhaust fumes of visiting ships, according to NBC News.

"They developed a (cleaning) tool kit with two swabs with handles on them. The swabs are kind of a type of terry cloth. It's kind of similar to what you would use on your car headlights, when they get hazy, to clean them," spacewalk specialist Devan Bolch said in a NASA video published before the walk.

The cosmonauts also took some panoramic shots of Earth during the spacewalk, identifying Australia and seeing the city Brisbane beneath them just as they dropped out of communication for a few minutes while they switched between communications satellites, Space reports.

The expedition is the 188th ISS spacewalk and the tenth for Padalka, who has spent more time in space than any other human, according to The Guardian.