Hi... Anything in body, tries to heal...so when we remove the cataract ..body tries to heal and form the natural lens again...it cannot do that...but few cells may form on the membrane which we place the lens. That is called opacification of capsule ..and need cloning.. Can be done in a simple OPD procedure. Once removed, it cannot come again

Cleaning is just an oversimplified term maybe  used by the  doctor or optometrist for your condition in which the capsule supporting the lens becomes opacified. It can be treated through lasers which are extremely  safe and effective

Sir most probably you are talking about ND Yag Laser Capsulotomy. After a few years of cataract surgery there can occur some whitening of the posterior capsule behind the Intra Ocular Lens which we call Posterior Capsular Opacity or After Cataract. It's a common condition and can be safely dealt with a simple laser.