1. Go get some cotton coil. You can get it from a beauty supply store or Amazon.
2. Cut the coil to the length of the area that is caulked on the backsplash.
3. Soak the strands in bleach.
4. Place the coil strands along the caulk.
5. Let it sit overnight.
6. Remove it on the morning and admire your clean caulk.