Pour white distilled vinegar into a cup. Wet a toothbrush with the vinegar.
Wet the lime-scale buildup by dripping vinegar onto the surface with the toothbrush. Allow the vinegar to rest on the lime scale for one to two minutes.
Scrub the surface of the lime scale with the toothbrush. Lime scale will not hurt you, so place your hand under the pipe to catch the lime scale as it falls off the pipe.
Add additional vinegar to the toothbrush and continue to scrub until all of the lime scale is gone.
Rinse the pipe clean of debris and vinegar with a rag dampened with clean water.
Dry the pipe off with a towel.