I'm cleaning my 10 x 12' cedar deck. Two years ago, I washed it with bleach. It cleaned up fairly well. I stained it with one coat of Sikken Cedar stain. Now the dark grey film has returned with a vengeance. There are trees coming right up to the deck, and it gets the morning and midday sun (the deck faces east). With my portable belt sander, I'm able to sand down to bare wood, but it's slow going. After several hours, I've cleaned 1/3 of the deck. I looked at a large vibrating sander (the size of a big buffer) at Home Depot to rent ($41.00 a day), but I'm not sure if a vibrating sander, even though it's a big one, is going to cut through that film very agressively.
Any ideas?
Thanks! Scott in Minnesota