None of the commonly available strippers will touch poly in my experience. I've tried most of the "eco-friendly" ones like citru-strip, they just don't work. I've stripped one bass, did it with a heat gun and the plastic scrapers you can get at any hardware store. They dull very quickly, but you just re -sharpen with sandpaper. It takes a while, but the plastic scrapers don't seem to gouge like metal. I used a cheap Harbor Freight heat gun, plenty hot for that job. On the one i stripped, the black poly and clearcoat came right off in sheets, but the primer was a bitch, ended up sanding about half of it off.