Continually brushing it off with a very soft brush, avoiding the actual heads as much as possible. For the long run you might consider removing it from algae prone spots. What I did was look at my tank to see where algae grew the best and then placed it else where.

If your tank is cycling through a case of algae, in which case EVERYthing has algae, you'll have to tough it out, figure out what's causing it, and incorporate some more algae eaters.