We have purchased a federation style home, which had the front painted white. During the removal process, we found that underneath several layers of paint, plaster of paris had also been applied in a random way, and is proving very hard to remove. We have tried HCL, as spirit of salts, but no luck. Also tried a caustic paste, but it still won't shift. Any product would have to be readily accessible, and relatively cheap. The house isn't that big, and it only the front of the house, but there are still alot of bricks that need plaster removed. Any ideas?