There is a product that will remove Dried Silicone, Wet silicone, Liquid Nails®, Polyurethane Caulks, Expanding Foams, regardless of what some say is impossible! There web site is http://www.re-mov.com
Re-Mov Silicone & Adhesive Remover easily and quickly removes silicone and polyurethane caulks from a multitude of surfaces without damaging coatings or surrounding materials.
It's totally effective and absolutely safe on metals, including aluminum, glass, reflective glass, mirrors, wood furniture, floors, cabinets, fiberglass, gel coat, Plexiglas, polycarbonates, most plastics, most carpets, vinyl, fabrics, upholstery and clothing, varnished, urethaned or painted surfaces, stone surfaces, cultured marble, tiles Formica, Corian®, ceramics, enamel and porcelain surfaces, and brick.
Re-Mov Silicone & Adhesive Remover also cleanly removes butyl and urethane sealants and adhesives, glue, foam gasket tape, film or foam attachment tapes, including very high bond acrylics, transfer adhesives (emulsion or water based), duct tape, coatings, chewing gum and most other sticky substrates and their residue from all surfaces.