My friend picked up a CJ that sat for awhile. While doing the front brakes we noticed that the passenger side caliper would not bleed easily, as if the line was clogged. Upon further investigation, we noticed some gack at the bottom of the master cylinder. This weekend we plan on replacing everything except the steel lines. If they are clogged, is there a solvent i can run down them to free the gack with the help of an air compressor?