There are several methods to remove caulk, including blades and scrapers. One of the most effective ways is to use a plastic scraper or a credit card. It gets the caulk off without damaging the walls, shower, or bathtub.
Another great product you can use is caulk removing gel. It reacts with the caulk, softening it, so it comes off easily. This is useful when you have stubborn spots that no amount of scraping will shift.