You can buy some caulk remover at Home Depot or Lowes. Find out if the caulk you want to remove is either latex or silicon. Latex caulk remover is easy -- you just squeeze it out of the tube and let it sit on the caulk a few hours and then it comes right off. I had to do this in my guest bathroom and it was not difficult.
Now silicon caulking is a real challenge to remove. I had to do this in my master bathroom. I am not sure but I think you have to use rubbing alcohol and then scrap it off. I hired a handyman to do this dirty work. If you go to one of the home improvement stores, ask the sales clerk about removing silicon caulk -- they may have something new on the market now to remove it easily.