You can try to scratch it out of the fibers with a razor blade. Unfortuntely caulk is essentially a pastic substance so once it dries it will bond with the fibers of your jeans.
Depending on the kind of caulk a dry cleaner or professional cleaner should be able to remove the caulk. Bringing the caulk container as well will help.
Read the label of the caulk. If there isn't any information call the manufacture. If its washable, soak in warm water with a little liquid soap and rub. Usually these caulks are water base.