Bar Keepers Friend is in the cleaning products aisle at both Home Depot and Lowes (Lowes has cleaning products near their paints; HD's is many aisles away near garden products). I called BKF's 18004335818 info number and asked if it's "mostly" oxalic acid, since it's the only ingredient listed. They said "yes". Neither HD nor Lowes has a product called 'wood bleach' in current inventory, according to help I got in both stores today Aug 28, 2012.
It's not like Bar Keepers Friend - it's soft, and shiny and kind of sticky.
It is used to clean dirt and clay off of rocks, so mining companies that sell to the public like Ron Coleman's Mining Company sell it. You can get something like a quart bag of it so you don't have to get a ton.