Motsenbocker's Lift Off 41145 4.5-Ounce Spray Foam and Silicone Caulk Remover Safe on Showers, Baseboards, Stainless Steel, Ceramic, and More Water-Based and Biodegradable, Clear - Waterfall Foam Sealants - Amazon.com
The best tricks: How to remove caulk
How to Remove Old Caulk From a Tub, Shower, or Sink