I'm in the middle of replacing a "window" made by the PO. Basically a house window with wood around the edges cut to make the house window fit into the original window frame. That plus copious amounts of some unknown sealant.
With the old window and frame out I'm fabricating a new aluminum frame and am having a pane of glass cut to fit it. The problem is all the old sealant that's globbed all over the exterior skin. It's a combination of silicone and some unknown brittle sealant with a hard sandy texture. I've considered using a non abrasive disc on it to remove it, and while I'm sure that would remove it, I think that it might also put some deep scratches into the skin. Any suggestions on how to remove the old sealant?