Ragging can be pretty traumatic. I can understand that you have been tormented by the experience and are still experiencing negative emotions post that experience.
While you have elaborated this emotional state and felling pure/ impure and the cleaning of parts etc, I would want to know that in your mind, have you ever thought it is very senseless to have these thoughts that after touching it has become impure, and do you also think that these thoughts of impurity come to you repeatedly, disturb you, and affect your daily functioning.
On the same note the acts of cleaning yourself / rubbing yourself – are they repeated many times affecting your schedule etc. Don't you think that by once cleaning it would have been cleaned and do you think the repeated acts themselves are senseless but the underlying anxiety prevents you from ceasing these acts even if you feel that they are not required or should not be done.
If the answers for most of the questions are yes, you may be having a specific psychiatric disorder and would benefit by visiting a psychiatrist who would be able to start you on specific medications and help you to engage in specific behaviour therapy for alleviation of the problem and the distress associated with it.