Hydrochloric acid can be used to dissolve calcium carbonate and iron sulfide scales. However, iron sulfide chemically reacts with hydrochloric acid and produces hydrogen sulfide, a highly toxic gas having the odor of rotten eggs. Due to the high toxicity of hydrogen sulfide, safety provisions need to be implemented.

Calcium sulfate is not soluble in hydrochloric acid, but chemicals are available that will convert it to an acid-soluble form that can then be removed by the acid. This process is slow; however, because a two-step process must be repeated to strip the scale layer by layer. Thus, the removal of calcium sulfate is more difficult than the removal of calcium carbonate.

Practical means of dissolving barium or strontium sulfate are not available. These hard scales can be removed by mechanical means, which is a time-consuming process. Mechanical removal of scale can create a disposal problem for the resulting waste material and possibly could result in contamination by naturally occurring radioactive materials (NORM).