Come into possession of a huge roll of black 3mm filament. Been lying on the floor of a workshop. Its all dusty, not on a drum. Can it be saved?
It may not be any good. You definitely want to clean the filament otherwise all the dust will start piling up in the extrusion nozzle and clog it. You would also want to see if you can get a large enough spool to re-spool it to make sure there are no tangles.
As for how long to dry… that depends on the type of filament. Do you know what it is?
I’d print one of these and put a single drop of oil on the sponge. It cleans dust off filament very well.