Even though clean and smooth inside wall is extremely beneficial, flexible and curved tubing is particularly difficult to polish with conventional polishing methods. Without a smooth surface, it is very easy for the flowing medium to be trapped inside a hole or a defect due to the slowing down of the medium because of the shape. The chemical polishing process optimizes the cleanliness and corrosion resistance of the tubing. In medical applications, bacterial colonies can easily grow and contaminate the tube if there are holes, defects, and uneven surfaces