Assuming the balconies are common property and there has been no by-law established to allow the additions and modifications, I think you can restore them to what you might reasonably assume their original state was.
You might also tell owners that if they wish to re-enclose them, they will have to apply for owners corp approval and (probably) council DAs.
But before all that, it might be worth canvassing the owners on what they want, individually and collectively. You may be surprised and discover a majority want a “cleaner” look.
You might also explore ways of either establiching shared laundries or some of the more modern ideas of laundries in cupboard spaces.
Older buildings tend to waste a lot of space compared to newer builds, so with some creative thinking you may be able to have laundries AND balconies – just not in the same place.